Thus for example, just because their are innovations in physics that are ongoing doesn't mean I can't safely dismiss perpetual motion claims.

Yes, but a perpetual machine would be an innovation par excellence, wouldn't it be? Especially for you and me and everybody else, who are almost certain, it's not possible.

And while there's constant research in my own field (number theory) I can be dismiss a lot of claims of proofs of major theorems by crackpots even though there's ongoing research.

Yes, again. But whatever is quite familiar for you, what you can easily grasp, is not a big innovation for you. Maybe important, but not that innovative. You have thought similar thoughts already.

Thus for example, I have a friend who is a physicist who considers it extremely unlikely that we will ever have room temperature superconductors.

I tend to agree with him. Anyway, superconductivity would be a very important but not a very innovative thing. Unless based on some completely unexpected principles. Then it would be innovative too.