There's a extensive letter by Steve Jobs in the official Apple site where he explains the reasons why he didn't want to back Flash in the first place. I've always been a big Steve Jobs' fan, but also I always had some doubts about this point. I mean, if you read his official biography you'll immediately notice that the most important motivators for Apple and all the other technology companies is not exactly technology itself, or innovation. It's money. As simple as that. And I think Jobs had his own business reasons to begin a "war" on Flash.
However, as the time went by, Flash lost a lot of territory, especially in the mobile field. I can't tell if Steve Jobs was right with the technical reason he gave, but I'm sure he always won at the end. And maybe now we could be certain about it.
Youtube has announced in its official Engineering and Developers Blog that they'll use HTML5 as default for its videos.
This may be the end for Flash, since they had Youtube as one of their biggest (if not the biggest) clients. Flash has been consistently loosing market share during the last months, as you can see in the following chart:
You can consult some other related charts here.
The fall of Flash begun as soon as the iPhone was released for the first time. A long time ago, Apple lost against Microsoft but not because of bad technology choices, but for business moves that gave Microsoft and edge. Right now, I'm not in the position to say if Flash was really a bad choice for mobile devices, but I'm sure that the business decisions dig the grave for Flash back when the true Smartphone market was raising.
On the other hand, we could evaluate the technical reason given by Steve Jobs in his own words:
As a conclusion, and given the circumstances, maybe it's time to bury Flash once and for all...