Earlier quoted context omitted.
I was originally in your shoes, but after my first real attempt at writing a game in js/html I came to the conclusion it's still a ton easier in flash. If you are talking about something more static (e.g. a non-game application or a fairly static game like a match-3) it's probably less of an issue.
Yeah, it's easier -- but flash games are rather pointless. Does anyone actually make money selling flash games? You'd be better off learning Cocos2d and developing something that actually makes money, such as an app.
I hear FarmVille makes some money.
And game development for iOS and Android is perfectly viable in flash since AIR 2.6 and specially 2.7. There are a few features that are ok in PC that kill the performance in mobile, but for the most part you can make anything you want with flash for mobile and have good performance. Talking form my own experience.