Yeah but he can't elevate nationally and that really limits his splash. If the right wing media keep hyping him up that increases his profile but ultimately he's still only the mayor, even if it is NYC, he's not eligible to run for President and that's where the real danger would be.
So you're looking at him maybe turning into Bernie 2.0 is he became a Senator but without the ability to run for President.
That's exactly my point, since he can't run for President, even if he's governor of NY he's still not really a threat to the power structure of the country, even Senator. He'd be Bernie 2.0 but unable to run for President. Not saying he wouldn't be influencing politics but it's a massive card off the table if he can't run himself.
Timing wise odds are he'll be in NYC long enough for Chuck to be replaced by someone else for 40 years. Kirstin seems firmly in her seat, so I'd say he's most likely Governor after mayor, just a moonshot guess.