The fact that crisis-driven projects are successful points to the problem: delays.

In any sufficiently big project, I'm coming around to the opinion that there's some amount of timeline that results in an effective "never".

I think it's just that at some point, people stop caring? Or at least feeling like they have any motivation to hustle?

And once that happens, the end result in lethargy and a grinding halt to actual progress. Even if checklist items seem to be getting ticked off.