They may. I think the government should probably tax the diff in salary in those cases. The problem is, that is probably incredibly hard to define and pass as legislation or whatever has to be done.
H1B and offshore jobs can be beneficial to America though, and that was why the program started. Sufficient guardrails just never went up and now there is opportunity for some abuse. But that abuse isn't across the board, there is still beneficial H1B and offshoring going on mixed in with abuse.
"I think the government should probably tax the diff in salary in those cases"
How would that work if the remote people were employed by a different company that was given a contract by the home company to provide certain pieces of software or specific computing services?