The 3rd world immigrants are a huge reason why the cost of living has gone up so much. Adding more people to any finite space is going to reduce the amount of resources available. If the people added come in with high skills, education, and are law-abiding, they can still be a net positive to the economy and society as they produce more than they take. This is basically how the legal US immigration policies work. If you are smart, skilled, motivated, and law-abiding, the US welcomes you with open arms.
The migrants that Europe has added, however, have been enormous net negatives economically as they have dramatically increased the crime rates, taken up space and resources (increased cost of living), AND they don't even produce more than they're worth economically. The end result is you have higher costs of everything, less space, more crime, and a substantially shettier country to live in all around.
Everyone should look up the term "human capital" if they're not already familiar with it.
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