Yuck, what a boring place. The original apartment was so much cuter, on the second floor of Phyllis’s beautiful Victorian era house. I know Mary needed her own bedroom and was tired of the sleeper sofa. Couldn’t she have rented Rhoda’s place after she moved out? Made that her bedroom? She had to have been making more money by then. At least she could have found a nicer place than that boxy drab apartment in some nondescript highrise.
I’ve heard that suggestion before about Mary renting Rhoda’s apartment and that could have been her upstairs. Makes sense.
Perhaps that would have happened in real life, but it wasn’t going to happen on the show. Mary Richards just wanted to make a big change in her life. I think it might have had something to do with the fact that both Rhoda and Phyllis had moved on and by remaining in her apartment Mary felt stagnant. She also probably missed them and was always reminded of their presence or their absence by staying in the same place.
I never loved the new place, but at least her living room furniture was nicer. I could never stand that ugly brown sofa.
There's also a real-world reason -- namely that they were no longer able to film new exterior shots of her old place -- because the real owner of the house was sick and tired of people ringing her doorbell, wanting to come in and see Mary's apartment.