Mamdani is fairly unique among Democrats in that he's calling for output legitimacy, something that Hillary Clinton outright rejected because she thought "things might just go wrong despite me doing the right things". Trump would, of course, make excuses about anything that goes wrong or deny that anything goes wrong but he's never going to make a show of low agency the way Clinton did.

https://macleans.ca/general/two-concepts-of-legitimacy/

tbf as a leftist my wariness of anything called "abundance" is that people to the right of me have been using that word and words like it for decades and the outcomes tend to go one of three ways:

1) nothing actually happens

2) the thing labelled "abundance" actually makes things worse for the average person but makes the aggregate economic statistics look good

3) the thing that gets delivered is so pre-compromised and watered down that it bears only the most tenuous connection to what was actually promised ("free healthcare" -> "a conditional subsidy to buy health insurance and an additional open enrollment period" and "student loan forgiveness" -> "actually processing the forgiveness for people who were already legally qualified under PSLF and not much else for anyone else")

and in the mean time it's used as a reason why democrats are abandoning common cause with people like me. "Queer advocacy is the right thing to do but it's a loser at the polls. Let us make you rich instead, then you can be your own advocate" and then they just sorta...don't do that.

but also as a leftist if I couldn't agree more with "if Democrats are to be the party of government, they have to become the party of making government work; and too often, it simply doesn’t". As the only party that wants things that are at least occasionally compatible with what I want the democratic party's ability to not get anything done regardless of the resources they have to hand is astounding.