I would say athleisure is a recent development. 10 years ago you'd see far fewer women wearing tight leggings outside the gym. Heck, even in gyms you'd be hard pressed to see the kind of tank tops and sport bras you regularly see nowadays [1]

N.B. I'm just noting the phenomenon, not commenting on its merits

[1] https://www.vice.com/en/article/women-are-intimidating-men-w...