Based on my purely anecdotal experience, engineers that would be easy no-hires in Chicago get scooped up into senior roles in the valley because everyone there is so desperate to hire anyone who can fizzbuzz. It's the best area to be in if you're one of the best... and also if you're one of the worst. Top-flight talent exists in these "hotspots" but they're all "Unobtanium" for anything that isn't a unicorn, IPO'd, or founded by one of their friends.