@ProtonBadger@SubArcticTundra technically windows hasn't had much of it's ui ideas change since 95 (8, 8.1 and 11 were major departures and part of the reason their so disliked).
I would say it's probably more kde copying aspects from windows then sorta going their own path with those ideas.
Visual style that was started with breeze and 10 is debatable, graphic design wise 10 was just a simplified 8 reflecting design trends of the time while Breeze was a massive departure from sqeumorphicism