Earlier quoted context omitted.
The best feature of flash was that it was so easy to disable. Because 99% of the use was annoying ads that pinned your cpu at 100%. And that was Jobs argument, that it was too resource intensive. Predictably though, now that annoying crap moved to "newer" tech (javascript) and now we can't disable it as easily or without as little consequence. Just as resource intensive though...
I never bought the benevolent technical angle for not supporting flash. I'm pretty sure Apple strategists knew the value of the gate-kept platform, the app-store revenue stream. The pivotal point was that flash would break this stronghold by allowing rich applications that are reasonably self-publishable. (Excuse me while I go rinse that sentence out of my mouth)
(To give you an idea of how bad it used to be, Qualcomm’s BREW platform launched with terms for developers like $50k per carrier per app to be listed AND a percentage of your gross revenue – not just the app, everything!)
The performance problems were very real, too, at a time when they were sweating every bit of RAM and CPU but the bigger problem was usability. Android kicked Flash to the curb, too, because while it was technically possible to make it run on a phone with a touchscreen was horrible — even the Android superfans barely talked about it as an advance because nobody liked Flash even if they had their phone plugged into a charger.