People are looking back with rose tinted glasses, I think. This was an era where you could build rich media with absolute canvas values and it would look great and it was easy for an artist to take that canvas and do things.
The iPhone killed flash but not just in the obvious way. These days everything needs to be reactive and run on well on mobile hardware. Even if iOS supported flash it would need to be a different beast. Different screen sizes, an explosion of aspect rations, heavier security requirements, accessibility, touch controls and more led to the downfall.
I remember sideloading the Flash Player APK on my Android phone around 2013 (they stopped official support in 4.1) and most of the Flash content was effectively unusable even then.
Pecking on a tiny video player with your finger to change volume, quality, or playback position was a terrible experience and the battery drain wasn't great either. Watching videos outside of YouTube was a terrible time for phone users before sites transitioned to HTML5.
Adobe Air could produce executables iOS and many other operating systems and environments. I have seen many successful mobile games done with Air. Flash Player is a virtual machine and swf is compiled bytecode. It could be ported to any hardware and OS. Death of Flash is not technical, it is political. SWF format and Flash Player is proprietary. They chose to kill it instead of supporting someone else's technology.
The iPhone killed flash but not just in the obvious way. These days everything needs to be reactive and run on well on mobile hardware. Even if iOS supported flash it would need to be a different beast. Different screen sizes, an explosion of aspect rations, heavier security requirements, accessibility, touch controls and more led to the downfall.