Earlier quoted context omitted.
> the Republican anti-immigrant platform because it seems to me there is significant brain drain from many countries to the U.S. and that contributes to our success. Explain how unskilled illegal immigrants contribute to our success. I'm open minded but I've yet to hear anything convincing. No one is opposed to the legal immigration of skilled workers.
Why would we be opposed to unskilled immigrants? The majority of the people who came here from Europe in the 1700s and 1800s were laborers, factory workers, farmers, and other simple occupations. Why are we pulling up the ladder behind them? Did you want to freeze the US as it was circa 1950? Things change man. The US isn't forever, anymore than Rome was. You gotta stop trying to fight the current and pretending that…
The welfare state did not exist in that time, so the cost of absorbing immigration was confined to acculturation. Immigrants had to quickly start generating value or perish. The incentives are radically different now and the marginal cost to society of absorbing each additional immigrant is much higher.
US government spending as a percentage of GDP remained low single digits until WW1; it is roughly 35% today.
> You gotta stop trying to fight the current
You must also remember that the natural state of everything is decay, and the natural state of mankind in particular is "solitary, poor, nasty, brutish, and short". The current grinds everything down to sand. It is incumbent upon everyone to fight the current in the way that affords the greatest benefit to society.