Pathfinder already had a steady fanbase to fund Paizo's releases before the OGL fiasco, and it will continue to do so. I do expect maybe half the current community to die out in the long run, though, because data from the subreddit shows that members doubled the month after the new OGL ras released. Many people just talking about it and not playing as well.

Pathfinder 1E is built on the 3.5 version of D&D. The OGL at that time was too permissive so Paizo copies the system, made their tweaks and flavor changes, then released it.

Pathfinder 2E is a new system that doesn't rely on anything from D&D at all. The new OGL changes are not to target Paizo, but rather to target creators making modules or shows based on D&D 5e. They only changed the license for 5e.