Did you look at the Bloomberg article I linked in my original post? It says that half of the H1-B visas are taken by staffing companies and they pay their staff significantly lower than the US laborers they are replacing.
Better instead to look at larger scale studies out there, including the ones I mentioned in the comment I linked. The results are much more nuanced, but generally they find negligible or mildly positive impact on native workers, suggesting they are largely orthogonal to foreign workers.
The point is that the dynamics are more nuanced than simple supply vs demand.
Every h1b role I see posted at my bank pays more than I make so I don't get the lower paid comments