My diagnosis is in that spike. I got diagnosed late because it took that long to get away from my autism denying parent and enough time living on my own to start wondering about my "weird habits", especially after starting to meet others "like me".

It stopped being a disability in my mind and started being more like a superpower, and eventually out was just who I was and y'all can just deal with it. Of course I leaned boundaries and social graces because we live in a society, but how I view myself and other people definitely changed

So I think it has a lot to do with how this generation and previous ones changed how they handle autism.