It's tough because every accessibility plan NYC has had is blocked by New York State refusing to fully fund the MTA. All new stations are ADA compliant, but the old stations are ~100 years old and there literally isn't any money to refit them.
The city runs a car/van/bus system specifically targetted at people who have accessibility concerns, but it's also woefully underfunded for mostly the same reasons. Buses are I believe already 100% compliant and provide access to all of Manhattan.
Further, most of the core stations are situated such that there is no "easy" way to provide elevators. Making even half of the existing legacy system fully compliant would probably cost billions. The state will neither pay for it nor let the city pay for it internally.
The good news is if the lawsuit succeeds, the state will be forced to pour billions into the city.