H1s cost $6000+ and are available 4 days out of the year in April, and even then you have a 33% chance of getting one. And should you get one you can't start until the new USCIS fiscal year in October.
What about that makes you think they'd rather hire a foreigner? The green card burden is years and many more thousands of dollars. Those people are probably just really good.
Also, your statement about H1s getting paid way less isn't usually true, they're required to be paid the prevailing wage for the job they're doing in their geographical area.
Now if you're talking about body shops, well that's a totally different conversation and needs to end but if those people were sponsored directly by your employer there's some good reasons. And if your employer is using a body shop you should be mad at them not USCIS -- for this, there's plenty of other reasons to be mad at USCIS haha.