Non-competes eventually end, and IIRC in the finance industry they often pay you for the duration of the non-compete.

After a couple years, sure. It would take a really compelling raise to make up for all that time without working.

Not in California or specifically Silicon Valley. To pick another financial center of the world.

California is essentially unique in this way, while people are trying to generalize about centers in general. In no other center can you actually quit your job for a competitor; it’s doubtful that the competitor’s presence is relevant.