I fell down a rabbit hole a couple of weeks ago, and
have emerged with a diagram I've pulled together of the various non-excursion/sightseeing ferries in New York City:
View attachment 52343
More comments at the link, but to me this underscored a few different points about New York City transit:
1) The number of overlapping public and private companies is remisicent of the continued siloing of Metro North, LIRR, NJ Transit, etc etc.
2) Judging by frequencies and routes, ferries are most popular in places without enough fixed crossings (e.g. the Hudson River)
3) Even with PATH, there is still apparently demand for additional cross-river service into Downtown
4) The institutional complexity implied by this map is daunting, and reflects my general argument that New York is so one-of-a-kind that it is a near-useless point of comparison for many transit discussions