Flash was kind of terrible, though. It was proprietary and the creation tools were largely inaccessible. Some of the plugins only worked on windows boxes. It had a lot of the same issues java applets had with accessibility. Today's ecosystem should be able to support basically the same creations in a much more portable, accessible, performant format. My understanding is that even the flash runtime itself has largely been ported to html/js/webgl/canvas. So why we don't see this is very curious indeed! It must be the lack of accessible animation studios.

I don't mean to diminish anything you say, of course, it's all true and these flash games are a cherished point of my childhood. But the true loss hasn't been flash itself but the creative tooling that enabled a generation of artists to express themselves and create fun things and the communities that arose around it.