[TuringNYC]

One case where I can see a suburb welcoming an annexation is when pension problems get out of hand. There are hundreds of small municipalities which have promised policemen, firemen, and others huge pensions. Many of these pensions are underfunded and only survive by "borrowing" from the budget and/or "borrowing" from future generations' pension assets.

It is unclear whether the PBGC (https://www.pbgc.gov/) will bail out the small municipalities. But i'd bet that Illinois, California, LA, NYC get bailouts. In such a situation, it would make sense for a municipality to join in with a "too-big-to-fail" entity.

I'm not a local government expert, but i'm seen enough bailouts to think these are decent guesses.

[Kamq]

Really depends on who is in power at the time.

Famously Ford refused to bail out New York when they went bust back in '75 (he did later sign legislation giving them loans, but my understanding is that those were paid back).

Probably also depends on the trifecta, since during the Obama administration (republicans controlled the house), the city of Detroit went bankrupt and nobody bailed them out either.

Source 1: https://en.wikipedia.org/wiki/History_of_New_York_City_(1946...

Source 2: https://en.wikipedia.org/wiki/Detroit_bankruptcy

[dionidium]

Some of the smaller municipalities surrounding St. Louis have recently dissolved, for various reasons, but they're taken over by the surrounding County, not absorbed by the City.