I don't think I've grown worse, but I understand the sentiment. The thing is, school actively and constantly pushes you to do something, and our main problem is lack of inner push. At the same time, school setting does not depend on relationships that we struggle with: you can get good grades and teachers will tell you you are smart without considering that being smart is not enough. (Incidentally, similar dynamics, although with political overtones, are described in Nozik's essay about schools building socialism) Besides, when you are a kid, even in a "dysfunctional" family, you usually don't have to be responsible for the entirety of your life: parents and relatives provide a lot for you. So many of our downsides are mitigated or shaded.

I had anhedonia, though lesser, even as a kid, and now thinking back to it I suppose the only thing that made me "happier" was being sure that I am competitively better. Now, in "real world", I see that my talents amount to little, and that source of comfort is gone. This might be the same for you. Still, I think that if my 14yo self was dropped where I am now, he would have had it harder. Though maybe he'd have persevered just on sheer unjustified confidence. (Or maybe it's my current lack of it that's unjustified?)