So really the issue is the migrants are being abused and deserve better working conditions. With better working conditions where they receive equal pay and benefits as a local person then really companies would only hire visa holders if they were more qualified than local talent and thus more deserving of the position because of how many extra hurdles hiring a migrant and sponsoring a visa would add.
Basically correct. One other element to note though is that employers love H1B because they know it gives them huge power over the employee because the employee must leave the country immediately if they are fired and it can reset the whole process.
But once you take care of all the power asymmetries it would put US and foreign on an equal footing.
However I've also interesting trends where whole departments get formed all of one nationality and the siloing is huge.
