Comment by code_biologist

I'll add to my sibling commenters and say that there is a long history of critiquing the value of separation of concerns. One of my favorite early talks that sold me on React was "Pete Hunt: React: Rethinking best practices -- JSConf EU" from Oct 2013 [1] that critiqued the separation of concerns of HTML templates + JS popular in the 2000s and early 2010s and instead advocated for componentization as higher return on investment. I think people already saw styling separation of concerns as not particularly valuable at that point as well, just it wasn't clear what component-friendly styling abstraction was going to win.

[1] https://www.youtube.com/watch?v=x7cQ3mrcKaY