>pay the same taxes or more
Resident aliens pay the same tax rate, but do not qualify for many of the tax benefit tools (as an eg 401k is effectively useless because it becomes taxable income as soon as the person no longer resides in the US). Additionally one should consider that resident aliens pay significant tax with little hope of ever claiming a benefit, we do not get social security if unemployed (infact we get deportation), medicaid for our senior family members (they have no right to be here) etc.
> is far more likely to buy real estate
This is due to immigration rules. One cannot reasonably buy real estate unless they have some assurance of being able to stay in the time that buying makes sense. That timeline is 5-10 yrs at a minimum. H1Bs and other visas have 3 yr limits on them and can be revoked at any time.
> assuredly un-employ some American
You have little to no proof of this. I would argue the cost of bringing an H1B into the country (>= $10k) should make the existing American employee quite attractive.
I hope you can see that the deck is actually stacked in the local American's favor, and that a protectionist policy just drives jobs out of the country where they cannot be taxed at all.