False. We have unknown numbers of illegal immigrants being ushered in by governments every day; rampant fraud by foreigners, especially students, working in unskilled positions for cash or using a friend's ID; and we have many "skilled" migrants with rubbish qualifications that reveal themselves to be a sham the moment they go to work (potentially at great cost or risk to others). Don't tell me we aren't importing unskilled foreigners when almost every Uber and delivery driver I've had for the last 15 years has been an Indian.
Absolutely no actual Westerner is making the arguments that you have, by the way. You have revealed yourself as a foreigner trying to subvert our way of life. We don't care about a baby's "lag time", we love our children and couldn't care less if economic metrics don't. We certainly don't believe we "may as well" take in millions of Indians or Algerians to meet arbitrary economic goals rather than maintaining a harmonious and prosperous homeland for our White children. You cannot put a price on that.