"Android" is a software operating system, not a mechanical function control system. It was developed to compete with Apple's IOS. Apple's hardware systems are popular enough that IOS is found on billions of devices worldwide. That means that within a single Apple device, like a phone or tablet, they will sell millions, if not tens of millions of models each with the same physical controls and utilizing identical controllers. That makes it worth an after-market headphone (or camera, or speaker, or .......) manufacturer's time and dollars to develop products for Apple devices.
Other non-Apple manufactures spent billions of dollars to engineer hardware systems that could incorporate a non-IOS operating system within their devices. But the operating system controls 'soft' operations, screen brightness, volume, touch screen sensitivity, etc. Device manufactures like Samsung, or LG, or HTC, may develop its own "Player" sub-assemblies, or may buy and incorporate someone else's if the price is right. They each utilize vastly different physical circuits to control tiny electronic pathways which handle 'hard' functions, i.e. Play, Fast Forward, Rewind, etc.
With dozens of Android models out from almost as many different manufacturers, each of which uses differently formatted function controls, and may use different formatted controllers by model even within a given manufacturers line up, it is impossible to sell enough after-market functional control accessories for any given model to make it worth many after-market manufacturers time and money to bring to market.
Sorry, but that's one of the costs you pay for the individuality Android operated devices offer.
On the other hand, perhaps you should drop Massdrop a line once you have developed a simply designed, beautifully packaged, perfectly functioning, miniaturized physical controller for Samsung, Sony, Motorola, LG, Ericsson, HTC, Blackberry, etc. that will work with each and that someone like Klipsch wants to buy and incorporate into their headphones. Please keep us up to date on your progress, we're all pullin' for ya!