"I suppose it is tempting, if the only tool you have is a hammer, to treat everything as if it were a nail."
- Law of the Instrument

All Economists are universally indoctrinated into the same basic classical theories of economics. Using inaccurate mathematical models and pseudo-math to map the world as one big series of supply/demand curves.

What's worse. They delude themselves into believing there's a divergence of thought by using Keynes vs Smith as counter-examples. There's no divergence, both schools of thought are minor variations of the same basic fundamental concepts. Economic theory is -- and has been -- stunted for decades by Ivory Tower theorists who gave up on self-reflection decades ago.

Supply/demand do a decent job of mapping basic short-term fiscal trends at the expense of evaluating the impact of long-term trends and/or secondary/tertiary influences.

For example. If immigration limits were eliminated, logic dictates that high skilled labor would migrate en masse to developing countries with a low cost of living. ie maximize profit gains by reducing costs of living.

In reality high-skilled laborers act contrary to Econ theory. The vast majority of individuals who earn enough to cover their costs + future savings are more likely to migrate to western countries where they have a less purchasing power.

Social stability and professional opportunity present a value that transcends the assumptions of traditional Econ theory. It requires a long-term sociological investment (ie measured in centuries) to stabilize a multi-cultural society enough to break down the barriers of tribalism, xenophobia, caste, prejudice, etc.

Economists love to argue that the US recovered from the Great Depression due to the increase in industrialization following WWII. I'd argue that the US became an international super power because of the massive number of high-skilled exiles who migrated the US in search of safety/stability.

Decreasing the limits on immigration will only increase the 'brain drain' from developing countries. Further stunting their growth and competitive standing in the international community.

On the lower-skilled end of the spectrum, people who can't match the high standard of intelligence/talent will be priced out. For instance, I currently live in San Diego not far from the border with Mexico.

Most low-skilled Mexicans that move here either: permanently survive with a lower standard of living (ie for at least a generation); live here temporarily and send money back to their family in Mexico; or commute across the border temporarily for work.

I have a lot of respect those who sacrifice to stay permanently. The rest live a parasitic, transient existence. It's sad to see but I can't really blame them. Mexico is an unsafe, destitute, overpopulated, shithole; run rampant with corruption and extreme economic inequality. Given the choice, I'd probably do the same.

Illegal immigration doesn't hurt the US. We receive an abundance of cheap labor freeing up citizens to pursue higher-skilled professions or work in privileged positions managing low-skilled laborers. It hurts Mexico because -- by subsidizing their failing socio-economic structure -- we're delaying the inevitable watershed effect that would happen when a poverty-stricken populace is absent any alternative.

Instead of addressing the corruption, restructuring the government, and focusing on developing policies that lead to a more safe/stable society; Mexico defaults to a public policy of blaming the US for all of their problems while exporting their poorest/underprivileged underclass as cheap labor to the US.

The most intelligent and/or hardest working of those stay in the US, raise kids who are born naturalized citizens, receive a good education, rise above low-skilled labor, and prosper bringing more long-term benefit to the US overall.

The rest go as the wind blows. When the US economy contracts, opportunities for low-skilled laborers (ie construction, landscaping, etc) are cut and they immigrate back go Mexico.

The hidden impact from looser immigration laws is the potential for overpopulation. It's no good for anybody when a populace increases in size dramatically over a short period of time. Cultural stability depends on some semblance of identity.