I think there is more to the absence of well maintained vibe coded apps than just the need gap which you aptly pointed out already.
I have not seen anyone successfully cultivate a vibecoded app into a maintained one, or even a debuggable one. But I sure have watched several dozen brilliant people try very hard for the last half year, Monday to Friday, nine to five.
I don't think it's impossible but I am not seeing it happen, and everyone's afraid to ask why.