We have gigantic amounts of real estate effectively unoccupied in the united states, we are 179th in terms of population density for countries (almost the very bottom.)

Immigrants do not add "minimal demand", immigrants drive significant demand and expand communities, for example, bloomberg reporting that gas prices dropping may have a contributing factor that immigrants driving less this summer.

Lastly, our use of technology means that nothing is a zero sum game, we have created industries and growth through the use of various pulses of migrants and they are one of the core pieces of american success.