The net fiscal impact from the cohort of immigrants we get now is negative; they cost taxpayers more than they contribute. They take more from welfare and social services than than they pay in and more than current citizens. Additionally there is increased crime. There are so many of these that are not adding any economic benefit period, and for those that do, that benefit accrues to a small subset of business owners and politicians, not the general population of citizens. H1B expansion of foreign worker visas for example is bad for displaced American workers. The mindset that considers their own fellow citizens lacking such that they want to replace them with foreigners is insane to me. None of these western countries needs something such that they must get it from others; they can cultivate all of this from their own people, and birthrates would increase if not for the crowding out through increased costs especially housing, insurance, and depressed wages from importation of immigrants.
When I drive on the roads, when I shop for housing or apartments, when I want to pay for car insurance, when I got public spaces, parks, cities, vacation spots, got to stores.... I've never ever had the thought "You know what would make my quality of life better? If we had 100 million more people especially those that come from a different culture and speak a different language here and everywhere else right now". That is such a ridiculously foolish mindset, and disservice to one's own neighbors and such. Makes no sense to me.