You're gonna need a lot more money than that when ~40% of MTA total spending goes to pay pensions and healthcare for people that don't even work anymore by ~2040.

You need ~35% just to keep the system running functioning (which does not include operations - like the actual drivers).

That's only going to leave you ~25% leftover for everything else - and a non-trivial percentage of that comes from the Federal Government - which may not be there in the future (when all of their money is going to pensions and healthcare).