My conclusion---and some conservatives may not like it:
1. 1700-1800's People came for land and religious reasons (minority persecution)
2. 1800-1900's People came to fill roles in the industrializing economy. Craftworkers
3. 1900-2000's People come here attracted by easy money making opportunities. Sales and brokerage jobs, Scams, organized gang activity

Some very bitter experiences I had in the last few decades involved recent immigrants who had planted themselves in brokerage industries. One firm I dealt with had Russians, a Jamaican naturalized US citizen, east Indian....and lots of tricks up their sleeves. I don't have a lot of statistics but I think this is common. The birth tourism industry is a reflection of that, where fairly well heeled foreigners conspire to take advantage of us.

So if you like unbridled demand for money maybe you will approve of that. I wonder how many people are getting wrecked by it?