Is Day to Day living in NY city really that expensive ?

I do not mean for tourist but for people that permanently reside in the city ?
I have seen endless comical portrayals in films about young professionals barely making it in NY with their 75k starting salary but I have always wondered; how about people who work in the fast food industry,supermarket cashier and the like ,,,,in other words,non professionals !People who barely earn min.wage or barely above it ?
How can they afford a place to live and daily expenses ?

*Second question: How can people afford to take cabs on a regular basis ? Again in films you always see people taking cabs once or twice per day,,,,{20~30 blocks at a time}
While in New England:in a single day,I took 2 cab rides both trips cost me $50 there was no way in hell,I could afford that,not even once per week!