Comment by tptacek

Right, so that was exactly what I was thinking when I wrote that. All three of Flash, PDF, and the browser DOM are expansive, ambitious metaformats, containers for every piece of technology that has ever had a bug.

Your take on why Flash didn't survive is more cynical than mine. I genuinely think Apple threw up their hands at the prospect of attempting to solve a security problem on the same scale as the browser itself (something it took them a long time to get a handle on --- along with everyone else --- even after they put the kibosh on Flash).