> Do you think Google and Amazon might consider building out smaller regional offices in St Louis, Omaha, Cleveland if they weren't able to scam off thousands of workers on of H1B, L1, etc. visas each year to come work in SV and Seattle, instead of being forced to search for talented citizens outside of their areas?

This doesn't make any sense. Google or Amazon could "scam thousands of workers on visas" to come work in St. Louis, Omaha or Cleveland too.