>>5026325this is a long and opinionated blogpost
art tools and art styles improved and evolved. For me, I only started noticing stuff like that when I stumbled upon shadbase in 2013, I think that was also back when the sister site shagbase was up too. I was disgusted and horrified at first, but 14 year old me was also enthralled by it. I used to check it every day after school to see how else shadman would defile the concept of morality. How I stumbled upon it was PowerTrip (nostalgia) which led me to spazkid which led me to newgrounds. iirc powertrip was frontpaged for a long time or some shit like that.
My point is, it got big, got a lot of people into the digital art scene (for the hentai side of it) and then eventually it also leaked out into the non-hentai side of things. People started having an interest in art, and some started drawing and posting their own OC and whatnot. Flash and Photoshop were improving, and so was graphics and performance. Many of those new artists spilled out onto tumblr (like Mike Inel, Saltyicecream, Noill i think is how it was spelt) and developed fanbases of their own, who would get inspired themselves and yadda yadda yadda.
Basically it's like a game of telephone but instead of the picture getting more fuzzy it gets clearer for each generation.