Listen, I am as excited over the possibilities as everyone here!
The fact is that the cost of the engineering involved would obviously be a major factor.
I agree that (for the most part) that Governors Island would be a ghost town and that the subway extension would basically transport (for the most part) folks between Lower Manhattan and Brooklyn.
We already have alternative subway lines that offer that service right now.
It's the connection to Governors Island here.
As much as I would prefer a subway line extension, I feel that the Staten Island Ferry could serve Governors Island, but would make the trip to/from Staten Island much longer and would
not be popular with
most of the public.