I guess that really is a thing, eh? That concept is pretty foreign to me. How on earth are you supposed to do domain modelling if you don't understand the domain?
How many % of software is domain modeled? Must me a small minority.
Plenty if developed under consulting contract.
I’d say all (useful) software is modelling some domain.
Nearly 100%. They don't call it that or use that term, and almost never _design_ thinking about the domain. But the absence of a formal 'domain model' still results in domain modeling - it's just done at the level of IC who may or may not have any awareness of the broader implications of the model they are creating.