[qdpb]

Perhaps an interesting way to interpret what you're saying is that SF is bad enough that people no longer want to move there since all their surplus income will be consumed by housing costs (valid concern!).

But new immigrant salaries are as good as american salaries in terms of how much they can push prices up; so hiring H1-B is essentially similar to a pay cut for people (same $$, higher housing costs); following this pay cut some existing engineers will leave.

In the end you just end up with replacing some old engineers with new ones through a costly lengthy process.

This is the kind of absurd logical games one has to play in order to not acknowledge basic economics of supply and demand.