Despite what Sinatra would have us believe, if you can make it in New York it doesn't mean you'll make it in the mid west or any of the purple states. (Democrats haven't had a vote share lower than 65% since the 00s I think)
Yes, a record number came out to support him but almost as many came out to support anyone but him :(
My hope is that for all the naysaying, Mamdani turns out to be a technocrat in the Sewer Socialist model and shows the country socialism ain't so scary. The whole "laboratories of democracy" in action.
The progressive candidate that we've been craving barely cracked 50% in one of the more progressive places in the country.
This doesn't bode well for say, a very progressive Presidential candidate.
Lumping in former democrats as current ones seems more than a little silly.
Cuomo lost the Democrat primary, but he didn't switch his affiliation the way Kyrsten Sinema or Joe Manchin did. Because of the election rules in NY, he was still allowed to still be on the ballot, even after losing the primary, but was forced to be listed as an independent (because he lost the primary). Most normal people would see the loss as a sign they are unwanted, but not Cuomo.
The general election was first past the post, which in a race of more than two candidates rarely ends with one getting a majority of the votes. Had election laws prevented Cuomo from being on the ballot after he lost the primary, the options would have been Mamdani & Sliwa where all but Staten Island would have voted for Mamdani and you would expect to see the 65-70% votes for Mamdani.
Presidential election also has to deal with the Electoral College which ignores the popular vote all together, so not sure how you could focus on one stat when comparing a mayoral election to a presidential.