You can get by without a car in Boston as I do as well, if you work and live in the city.
Everyone in my circle who lives in Boston/Cambridge owns a car.
FWIW, I lived in the city and worked in a suburb, and also was able to live car-free without issue. This was in the days before ride-hailing apps, so I imagine it'd be even easier now. (Not technically car-free, I know)
The most amazing part of that commute was that most of the commuters actually did a cross-platform transfer at North Station from the Newburyport/Rockport line to the Fitchburg line. Again, one reason it worked is that the conductors on the outbound train would hold a few minutes of the Newburyport train was late.