A family of four in San Francisco with an income of 100k a year qualifies for housing assistance. Yes, I know, most families are two income now, but it doesn't speak well to this severe "shortage" that a critical worker with ultra valuable skills in short supply still needs direct welfare from the government to get by.
I'd say 200k for a minimum salary. I know that seems high to people, but remember, by and large we rely on labor markets to set salary levels. If you can't hire the experienced lawyer or financial analyst you want for 100k a year to work in a big, loud open office, we generally say that's the market's answer. Increase the offer and job conditions or accept that people have found higher value work to do.
Giving employers the right to control who is and is not allowed to come into the united states is a really, really big deal. It's a complete end-run around normal labor markets. If we're going to allow this, it needs to be a slam-dunk decision - yes, clearly this is a very essential and very well paid worker. To me, 100k doesn't come close, especially in the expensive areas around silicon valley (where many of the companies claiming a shortage and lobbying for visas are located).