> paying them much less to do the same damn job.
That isnt true. A SWE engineer working at the same level at Redmond gets paid the same band irrespective of visa status.
and how much pressure do they feel to raise the band over time when theres a constant stream of people coming in form another country who accept anything presented because its still higher than back home
sure, but there's the obvious counterfactual: if those engineers were scarcer, that level would likely be paid more