[miedpo]

It was licensing issues. Their audio system used some proprietary stuff, for instance. I remember reading somewhere (perhaps here) that some of the Adobe Developers wanted to open source flash in the 2011-2012-ish time period, and it was the licensing that prevented them from doing that. Can't find the reference though (sorry!).

Now most people just do things in other languages. Flash was a very nice platform to target though. It got a lot of things right.