True, but also there is very little advantage to wearing them in Y. After all you are sitting up all flight and the seats thin enough as it is, you need as much padding as you can get not less! Even in business very few change into PJs on day flights (compared to the number that do on night flights). It seems to be more about getting a comfortable sleep than being comfortable sitting down.
I also don’t know about others but my regular clothes tend be comfortable - even the trousers/slacks I wear to work often. After all in the office i’m sitting there for hours on end. If they weren’t comfortable I wouldn’t buy them.