Friends is pretty obvious to me, they are mostly born rich. Other than Joey and Phoebe, who are shown as working class / poor and are also this in the show. Rachel's dad is a surgeon. Monica and Ross were in the same town in long island, and dad was an engineer iirc. Chandler had a good job, and his mom was a famous author. So you combine that with the rent controlled apartment, it makes plenty of sense.
