Also remote work doesn't mean overseas, there is amazing talent all over the USA too that doesn't happen to live in the SF area.
I really liked this sentence: "The US has less than 5% of the world's population. Which means if the qualities that make someone a great programmer are evenly distributed, 95% of great programmers are born outside the US."
There are about 7 million people in the Bay area, 322M in the US total, so let's say 98% of the great people in the US are born outside of Bay area. There are no visa issues moving between cities or states in the US, but many many other barriers that have nothing to do with visas.