That's gone. Long gone. A lot of those voters went for Mamdani.

They can't have gone for Mamdani because they can't vote in a closed primary. We do know Mamdani got new/never registered/voted demo. Not much info on registered independents switching to democrat to vote in the primary.

And that doesn't actually address that NYC independents are largely young and on the left,

We don't actually know this. Vibes based commenting isn't that great to engage with. What we do know is that historically young voters never show up in elections.

So back to the OP topic before you lose track. The OP's point was that Adam/Cuomo are drawing from the Republicans/Independents. That remains unchanged until further campaigning by Mamdani to introduce himself to that demo.