Of course any random change could result in NYC dwindling away and not being able to pay it’s bond obligations any more. We don’t have to posit a radical change in how taxes are collected to imagine that, we just have to look at Detroit. The whole point of a bond is that when you purchase one you are betting that the city will still exist and still be able to pay the interest on the bond. That’s never guaranteed though.
And surely the pension holders would be fine, since those obligations will be funded from investments NYC has made whose performance is independent of its own revenue.
1. NYC funding sources will remain as they are today, or
2. NYC will transition entirely by 2038 to a land value tax?
To the extent and for the entirely rational reasons that you prefer #1, that's the negative to NYC bondholders.
> surely the pension holders would be fine, since those obligations will be funded from investments NYC has made
Assuming the pension was funded to 100% of projected obligations, this would be true. That is not the case; it's around 4/5ths funded.
Likewise pensions. My personal opinion is that anyone accepting a pension instead of better pay is not really doing themselves a favor; they’re taking on extra risk that the politicians won’t raid the pension fund or otherwise mismanage the city. I would rather just own the underlying securities myself, and eliminate the extra steps.
If you disagree, that's OK, but there's probably no way to make further progress in resolving that disagreement beyond a back-and-forth of "nuh-uh, yuh-huh".
I think it would be a large negative for NYC bond-holders and NYC pension holders.