It's not healthy when an industry makes it extremely hard (grind for months) for staff+ candidates to switch companies and expects them to prove themselves ever

It's not healthy when an industry makes it extremely hard (grind for months) for staff+ candidates to switch companies and expects them to prove themselves every single time. Not sure if other professions have similar strategies. Again, I've accepted it but this needs to be said. Also, you mention "a few relaxed months doing some closed-form problems". Sorry, they're not relaxed at all. You've to find time to do them after work when you're tired + need to ensure you can remember the patterns.