If illegal immigration is such a problem, why not fine businesses 5x salary for using the labor, for as long as it was used? There are a lot of systems in place to verify working status at this point. It eliminates any incentive to hire this cheaper labor willing to work for lower wages. The people coming will be coming for a variety of reasons but it won't be to take the jobs of the uneducated Americans
The employers/government don't do this because the prices of existing goods depend on that cheap labor. Money printing (deficit spending) through the economy has created many chaotic distortions and as a result of currency debasement has pushed the profit margins down close to zero for many businesses concentrating them in few hands.
These businesses can continue functioning for a time thanks to money-printer loans they receive in the form of non-reserve based debt to a primary dealer, but that doesn't solve the issue that the price of good inputs and the amount of money that gets circulated through work in the economy is insufficient to purchase basic necessities (its sieving, which often happens before a deflationary collapse).
On top of this already floundering problem which we cannot address, we have a demographics problem. The old, infirm, and disabled outnumber the young who work. There is no way forward without replacement as the costs of the old far exceed the young, and the only means to do so is through taxing immigrants who come here to work.
On top of this, China wants to go to war to retake Taiwan, and so securing the border is a critical national security interest/threat.
Its called a debt trap, any historian can tell you about how this and other behaviors towards empire (hegemony) culminate in destructive cycles.
The baby boomers as a cohort largely caused this, and have been orchestrating it in leadership so that the consequences of their choices don't hit until after they die.