The problem is that the vast majority of users are not capable of understanding that there is a trade-off of performance/battery-life when using Flash applications. For you, me, and pretty much everyone else on HN, this is fairly evident, and so it can seem frustrating that Apple doesn't allow Flash on their devices. But most people don't understand why these tradeoffs exist, they just have a phone whose battery mysteriously drains ridiculously fast, and sometimes web pages just become very slow to scroll.

Apple have made a choice - if they can't make these tradeoffs transparent to the user, then they won't allow the tradeoff to be made. I think that a vast majority of the population would agree with that as an idea, they don't want to have to deal with the complexity of modern gadgets, they just want them to work. If you're a user that figures that they can handle this complexity without shooting off your foot, then you're really not Apple's target market.

Of course, I can't help noting that you can always just jailbreak an iPhone, or get a dev certificate, and you can modify things to your heart's content - it is only "power users" - those comfortable with technology, but not good enough to be able to modify things themselves that find the iPhone platform frustrating...