The troll can price their licenses slightly less than the presumed legal costs. Then most victims won't fight.

Presumption of validity is what makes patent trolling more lucrative than other forms of predatory litigation. You're guilty until proven innocent, because the law assumes that the patent office is generally doing the right thing.

> Presumption of validity

It's just an evidentiary presumption that is trivially rebutted with any evidence.

> Invalidity arguments and IPRs suddenly aren't things?

I'm sure that you're aware that when you go to court, the result is never certain. Bad ruling happen all the time.

The vast majority of these decisions are against the patent owners, which I'm sure you are aware of. Also, I wasn't the one who characterized something as a patent that "should never have been granted."