Keep in mind, if I wrote a post arguing for a cap of 1.2 million a year, some people would upmod me because it's high, others would downmod be because it's too low, others would down mod me because it's too high, others would upmod me because it sets a firm limit. The number of strong opinions on this topic is bewildering (but not at all surprising).
I'm not completely sure how I feel about the issue, to be honest, but I'm an immigrant (my parents brought me when I was an infant), and I probably wouldn't have made it here under either the criteria that exist now nor the ones you are promoting.
What I know is that the dream of immigration to the US is about having a better life for you and your children. Don't the poor and uneducated deserve that dream just as much as anyone else?
Of course! The question is, how many poor and uneducated immigrants would you advocate naturalizing every year in the United States? 100K? 500k? 1.2 Mil? 4 mil? No limit? I feel that until people answer that question (and it will vary from person to person), there's no way to have a meaningful conversation about illegal immigration, which is about setting and enforcing limits.
As for "running out of land"... that's actually a little ambiguous. California could probably triple in population, and we'd still have some rural-ish areas in the extreme north. Japan, because of the density of its cities, actually preserved its rural character in some areas, and this is a country with a population density of 337.1/km2! In other ways, California has already "run out" of land. Ever drive from Orange county down to Tijuana? With the exception of a military base, it's basically sprawl all the way down. I suppose we could increase the coastal population by building high density housing on the coast...
Yes, but how do you prioritize? How do you control the drag on the social support systems of the country? How do you handle the gargantuan task of integrating these people into society?
And honestly I think that is one of America's greatest advantages. Reliance on credentialism ends up too often being just another class-based divide rather than meritocratic in any sense. Look at Andrew Carnegie, as an immigrant he had little to set him apart, but eventually he became one of the wealthiest men in the world. There are many, many more examples just like his. And yet so often we continue to say "yes, but, let's ignore that and pretend that we can filter people by merit". I don't agree that we can filter people by merit.
It makes sense to prioritize for the most productive/least diseased/least criminal/etc when possible to discriminate with reasonable certainty. Of course, this is not to imply that immigrants are neither unproductive, nor unhealthy, nor unlawful.
While rags-to-riches stories are great, riches-to-riches probably has a better expected outcome.
I don't see a lot of Canadian PhDs smuggling themselves in to the US, compared to Mexican laborers. Because there isn't demand to support the risk. The US seems far more willing to pay for laborers than PhDs.
However, even if that wasn't the case, You wouldn't see Canadian PhDs smuggling themselves in because they can get perfectly good jobs outside of the country. They don't need to go anywhere illegally, because they have plenty of options to go elsewhere. If it wasn't for the TN visa, I would be working in Europe, Asia, Canada, or nearly anywhere else, because someone from there would be trying to attract me.
It's not that there's no demand to support the risk. There's plenty of demand. There's also enough demand elsewhere -- if I had trouble getting into the states, some other company would have me, and I would be contributing to the economy there.
I would, however, put in a quota based on the amount of education, capital, and whatever else would provide an estimate of the benefit that this immigrant would provide to the country, penalized by the difficulty that the person would have in integrating and establishing himself.
So, for example, someone with a doctorate, a job offer from an employer, significant capital, and fluency in the language should NEVER have an issue getting into the country.