All tech debt I have ever seen in my 15 years of professional software development has been someone building too many abstractions or generalizations trying to future proof stuff.

That's interesting, because it's not my experience. A lot of the technical debt I see is that someone half-assed something thinking it would be easy to improve later, but the layer violations and inadequate tests make doing so a massive project, once it's become load-bearing.

That’s the opposite of the typical definition of tech debt.

Usually tech debt is debt—-ie something you take on to ship faster now at the expense of paying it in the long run.

I would say: if the feature is from a developer, high probability of YAGNI, if the feature is from a user, medium probability of YAGNI.