You can argue that both ways.

As public sector unions appears and pay & conditions improved, the only way that NYC mass transit has been remotely sustainable has been by consolidating the Moses empire into the MTA. The tolls provide the cash flow to sustain the system.

It's impossible to self-sustain the current subways, and the perpetual near-bankruptcy of NYC throughout most of the 20th century wouldn't have allowed for subway construction at all.

Moses's genius was getting the state government to give a shit about NYC and create the authorities to bond his projects.

Perhaps. But on the flip side the Moses era ended by the mid-1960's, which by now is over fifty years ago. There are a lot more reasons than Moses for why the idea of building new subways in NYC basically collapsed and still to this day hasn't been revived in any meaningful way.

For example there are reasons why the new 7 extension doesn't stop at 42nd street and 11th avenue despite that making perfect sense, and they don't have anything to do with Moses. The reality is that the entire process is just completely dysfunctional.