Flash was a superb technology, especially for people unable to afford "upgraded" hardware.

That ancient 2001 Sony VAIO cannot handle games like Steam's "Catch a Duck," or Playrix's "Gardenscapes 2." But it CAN handle the SWF versions. By pure chance I discovered it can handle Steam "Gemcraft: Chasing Shadows" but even if it couldn't the Full SWF version (I figured out how to unlock the Demo for Full offline play, especially as Armor Games no longer supports Flash) is just as good. The two "Glean" games and "Ion Drift Epsilon" are as good as anything WebGL can do, Steam quality. That Sony cannot handle "Panda Chunky" but yes SWF "Norby." Likewise "Breezeblox"/"Dublox."

In other words if SWF versions of even pretty intense games, especially with speed adjustments, came out then with a standalone Flash player almost any computer can play them.

Phooey on the late Steve Jobs.

As for HTML5- it is browser-based. There is not and will not be a single standard for browsers so cross-browser compatibility will always be a nightmare and any upgrade to a given browser can cause HTML5 to stop working. "Bejeweled" works to this day because Flash followed a single standard.

Power- ever try playing a WebGL game even offline?

Security- really? The biggest security breach took place because of politically-correct hiring. Ad-script, intrusive Javascript, believe me "they" know everything about you. Computer security is a joke and ending Flash has done 0% against it.