I agree with the sentiment, but using a 3.5 mm to 2.5 mm adapter on a phone is an absolutely horrible experience, especially if you're putting the phone in your pocket. You end up making a gigantic lever (length of the entire 3.5 mm plug + length of most of the 2.5 mm plug + extra length from adapter) that is acting on the little 2.5 mm socket in the phone. If you don't do damage to the phone (which I did, then repaired, then did again on my old Nokia phone), the whole thing is still super annoying to have in your pocket.
Like it or not, the 3.5 mm plug is going to be here for a while. We can either tolerate a slow transition to a better design (like we did with the 1/4" TRS to 3.5 mm TRS plugs) or come up with lower profile 3.5 mm sockets. You can make a 3.5 mm socket that is equal to, or smaller than, 3.5 mm at the cost of a little structural support. Let's try that.