I don't think I'd say rarely. Companies rarely allocate the design resources to produce that, but the companies that do are typically much larger, so the actual number of individual developers that get rich mocks is probably closer to 40-50%.

Depends who you work with, what's the intention, budget, etc. I'd agree this is a really good one.

I'm used to incremental Figma wireframe -> final product and working together with a designer.