It's not a dichotomy of maintaining the status quo or getting rid of H1b completely. At least in big tech companies, they do follow labor market tests and prevailing wage tests and so on that are designed to vet that there is an unmet need and that visa holders aren't underpaid. I won't deny there are visa mills and consultancies that game the system and pretty much explicitly just hire cheap foreign labor, but this is a thread about H1B in the context of Amazon layoffs, not InfoSys layoffs.
Given that the company sponsors them and come from lower incomes countries, they are ready to accept lower wages. If they do it I don't see why everyone wouldn't be doing the same.
It's of course hard to prove formally as those companies will comply with regs to make it look like they aren't discriminating (fake job ads, etc...). By the way in the US Indian consultancies got busted for this.