pbs uses flash video and apple decided to protest flash. no real reason to it. they could have put one guy on it 5 years ago and within a week it would have been compatible but they refused. flash isnt ideal for video but thats not a reason to refuse it to your customers.
The app store(and Apples 30% profit on games that would otherwise be FREE on ebaumsworld or similar. And they could not control Flash content) IS the reason for no flash. I am not going to lie, flash on portable, does not always have the performance, but for video it should have been fine
From what i see, html5 does not save any power so far(at least not in the desktop environment).
There are some Apps that will covert the Flash video files, but they are not free.
What about this An app to let you stream PBS to your ipad