And that's a perfectly valid statement to make on your own behalf. It strains belief, since modern athletic sneakers are engineered for maximum comfort and orthotic support, but I'm not calling you a liar. Your feet are your feet.
Yeah, my feet must be strange, but sneakers hurt. Always have.
We ask "why has athleisure become so prevalent?" or "why is tailoring declining in popularity and increasingly relegated to the realm of hobby?" Following Occam's Razor, answer is "because athleisure is more comfortable and practical to wear, is easier to maintain, is more versatile for a range of activities, and is far less expensive for the majority of people."
I don't think the response to this fairly incontrovertible truth is to contend that it's factually incorrect-- because it isn't. Rather, my response is "I wear tailoring because it's a joy for me to own and wear." The joy transcends pure comfort and utility -- and that joy is enhanced when the tailoring happens to be very comfortable. But for tailoring, comfort is incidental to its primary purpose. For athleisure, comfort is its primary purpose. Hence its ubiquity.
I think we haven't taken into consideration this:
Lots of people who are not used to wearing nicer outfits feel uncomfortable in them as it is outside their comfort zone. They feel stuffy or put on, and that leads to a sense that they aren't physically comfortable when they may well be.
Is it more versatile over a range of activities? I mean, athleisure wear looks stupid when it is worn outside of athleisure or for the most generic of chores. Contrariwise, does anyone look dumb in tailored clothing unless, say, perhaps we're talking about the beach or something like that?