See my replies to your statements below:
DWR takes up to a couple of days to lose its properties in continual rain, this is exacerbated by movement through undergrowth. I know of no jacket that has DWR that lasts through continual rain for extended periods- they all wet out eventually (except perhaps outdry).
My reply... You are hypothesizing about a 95/5 scenario, actually more like a 99/1 scenario.
How many times does someone actually become exposed to a continual, or non stop downpour of rain, (not a drizzle) over a period of two days straight, while crawling and bushwhacking through the wilderness?
I think that the guys out on the crab boats may experience this type of weather occasionally, but they are usually wearing PVC.
I worked in the wilderness areas of one of the rainiest areas around, SE Alaska, and I never experienced that type of situation.
I have also ridden out twelve hurricanes, or typhoons throughout my life, and again, I never saw it rain non-stop for more than a full day, except on one occasion way back when during Hurricane Dennis in Florida, where it rained for three days straight.
Now if I had been outside continually during those three days, I might have experienced the scenario you described, but I was smart enough to just hunker down, and only go out when necessary.
Finally, your statements are somewhat anecdotal, and with all due respect to you, you have no actual empirical evidence that was collected scientifically to back up your statement. Way too many variables, and just not totally factual, or accurate.
Perhaps we can agree that in normal day to day exposure to intermittent rain, which is what 99% of us will experience, a properly cleaned high quality waterproof jacket, that has a high quality DWR applied will last at least a month, and probably more. That's my actual experience.
The presence, or otherwise, of DWR does not change the waterproofness of a membrane jacket but it does change the capacity of the jacket to transmit water vapor through the membrane. No jacket can achieve this when DWR fails - which is one of the circumstances when then water vapor condenses inside the jacket.
Actually the presence of DWR does repel water, hence the name Durable Water Repellent.
When the DWR does fail, or wear out, the jacket material will wet out, and yes, at that point it will be more difficult, but not impossible for vapor to be transmitted to the outside of the jacket, but this is greatly improved by using pit zips, mesh pockets, and different types of hydrophobic clothing.
In practice, all waterproof jackets result in the wearer becoming damp or wet from sweat if the individual is engaged in aerobic activity in the rain. Even in ideal conditions (dwr functioning) the capacity of any of these membranes to transfer water vapor from sweat, in the quantity that it is produced, across a membrane to a humid ambient environment (i.e. when it is raining) is insufficient.
Most demonstrations of vapor transfer across membranes do not take into account the humid environment on both sides of the membrane in real world conditions. The membrane requires both temperature and vapor pressure differential to move water vapor across a membrane. these conditions do not exist when hiking through the rain - especially when working very hard or when DWR fails.
You are basically correct that aerobic activity, while hiking in the rain for example will eventually lead to the build up of moisture, and damp, or clammy feeling inside most rain jackets due to the inner lining of the jacket being unable to wick away all of the moisture that is created by your perspiration.
However, you seem to be making "blanket" statements again, and the buildup of moisture is dependent upon various factors such as the degree of exertion, physical differences among human beings, the jacket material, and fibers, the outside ambient temperature, the humidity level, and whether or not the jacket has venting such as pit zips, or mesh pockets, etc.
Again, as far as the jacket materials go, you did mention Outdry as an exception to your statement about waterproofing, and moisture buildup, but there are other jacket materials where great wicking and breathability performance have been confirmed and observed, such as with Polartec Neoshell materials.
Hiking on a level trail in a light snowfall in 10 degree Wyoming, will lead to different results than hiking in a place like a tropical rain forest during a heavy rain downpour.
One other factor to consider is the type of base layers, or clothing that is being worn under the jacket?
There are many base layer materials, and fibers that are hydrophobic, such as wool and synthetics, and wool/synthetic blends, meaning that they repel water, and move it away from the body, and then there are some materials and fibers like cotton that will retain the moisture.
Additionally, by embedding revolutionary particles like Cocona into the clothing fibers, manufacturers can actually increase the hydrophobic action, by literally driving moisture off of, and away from your skin and clothing.
So this is why you really can't make hypothetical, and unscientific blanket statements, as again, there are any factors to consider, but I understand your point, as most of us who have worn a rain jacket while exerting ourselves, have probably experienced that clammy feeling due to a build up of moisture.
In that sense it doesn't matter which of the modern jackets that you buy as none of them will keep you dry in the rain of you are hiking. The most valuable asset of any jacket is to prevent water ingress from the rain - which will displace the warm moist environment in the jacket with cold water. So durability, fit, hood and squall resistance is the optimal properties of any jacket as it prevents water ingress. the next best feature is ventilation (pit or torso zips) as this allows that most efficient method of water vapor loss - venting.
I disagree, as my jackets seem to keep me dry when hiking, and again, there are many different materials, some are better than others, and the variables that I mentioned above are a determining factor in just how dry your body, and clothing remain..
I agree on everything else, and have touched on venting previously.
The next most important property is DWR durability followed by whatever membrane brand you prefer.
OK...that seems reasonable.
If you are engaged in non-aerobic activity in the rain the membrane is more important as is activity in dry cold environment (i.e. snow) as the ambient differential in humidity is greater and the membrane can act more effectively to shift water vapour.
But if you are engaged in non-aerobic activity in the rain you don't need a membrane a pvc slicker would do and if you are in the cold, dry snow you don't need a WP membrane you need a softshell.
The truth is that a WP membrane is better than the alternative in most circumstances but this myth that, when hiking in the rain, they are guaranteed to keep you dry is marketing gibberish.
OK, again, much of what you are stating is pretty anecdotal, with not any empirical, scientific evidence to back it up, but I get your drift, as this is probably what you have experienced.
Let's face it, a lot of people's opinions are formed by experiential data.
I previously touched on the fact that waterproof jackets perform differently in cold and humid climates, versus hot and humid climates, and the type of jacket, outerwear, or clothing that an individual wears, needs, or deems appropriate for the environment where they are located, will again be based upon personal preferences, experiential data, and past performance, among many variables.
So admittedly modern breathable rain jackets are not perfect, definitely better than PVC, and some are better than others, but most if not all will keep you dry in the 95% scenarios that are commonly experienced, and perhaps jackets like Outdry are the best for those 5% or less scenarios.
I respect your opinions, as again, this is what you may have experienced, but they are somewhat different than my experiences.
I am always cautious about making hypothetical blanket statements, especially when they are based upon unlikely, extreme, and uncommon scenarios, that are not backed up by empirical evidence, and are a mixture of factual and anecdotal opinions and data.
Good discussion, and thanks for sharing!