You mean intentionally?

I think they just had the focus on features and speed and fps. Not security nor efficency (battery life).

How did you got that impression?

There is the universal hate for flash because it was used for ads and had shitty security, but anyone I know who actually used AS3 loved it.

At its peak, with flex builder, we also had a full blown UI Editor, where you could just add your own custom elements designed directly with flash ... and then it was all killed because Apple did not dare to open source it, or put serious efforts on their own into improving the technical base of the flash player (that had aquired lots of technical dept).