That may very well happen over time. Non-Bay workers may bid down the price of coding labor, and remote workers from disparate markets will bid against each other, and eventually some "global market clearing price" may be established. Economic theory doesn't operate instantaneously, though. It manifests over time as individual actors bid and negotiate. Remote work is relatively new and its substitutability is being figured out. In the meantime companies may exploit the inefficiencies (and so might workers).