I never met the man, so I can’t say with any authority why, but clearly Mr. Jobs was not a fan of Flash.
Adobe Flash (the engine that brought us many very cool animation tools.)
Maybe if Macromedia had not been gobbled up by Adobe, it would still be cool…maybe not.
Paraphrasing – Flash heats up our cpu’s…..too much.
That’s why iPhones, iPads don’t support Flash.