Guessing you're young! It's actually a good question. The old Campingaz stoves had a different attachment, incompatible with Jetboil, SnowPeak, Soto, etc. I bought one around 1990 and bought the last canister I could find around 2010. The company that distributed the stoves and canisters in the US apparently came up with its own stove with the new (and improved) type valve. I believe the Campingaz stoves are made in France, and they predate any of the current US brands by decades, so not really backwards.