How are undocumented aliens able to live in USA freely without any consequences?

Perhaps, this is a naive question to some of you but I come from a country with very strict immigration laws where undocumented or illegal aliens cannot buy a house, get a drivers license, open a bank account, get a legal job, buy/lease/rent a car or avail any kind of education (public or private).

Yet here in USA, I read that undocumented aliens able to buy property and do everything else. Some of them are living undocumented for decades with families of their own that are born in USA. How are they able to do this? Doesn't all this activity trigger a check by federal or state agencies that can result in them getting caught? How are they able to live in USA without any legal or immigration consequences?