> Any designer could open it and create interactive websites in it, no CSS or HTML knowledge required.

Please note that that "any designer" should have had at least a fairly decent knowledge of ActionScript because Flash wasn't all just magic and sparkles. I know this because I was one of them. Though I had to learn ActionScript by neccessity, I actually learned HTML/CSS/JS before needing to deal with AS

Good news is that HTML in canvas might bring back these cool days :)

Right. And Flash wouldn't end until Jobs won't come out on stage and say that Flash is eating the battery and Apple won't support Flash in their next iPhone, then Flash just ceased to exist. Apparently nobody needed innovative frontends anymore ¯\_(ツ)_/¯

There is no break pedal on this stuff, it just rolls down the hill until eventually it doesn't. It's a runaway process that feeds itself.