Have you seen the "average" users of LLM? They mostly don't care about hallucinations. It's like that joke[1] "Computer says no", it doesn't matter what is true or real, only that the computer said it, so now that's true in their mind.
Personal anecdote: I work with beginner IT students, and a new, fun (<- sarcasm, not fun) thing for me is the amount of energy they spend arguing with me about basic, easily proven Linux functionality. It's infuriating, the LLM is more believable than the paid professional who's been doing it for 30 years...
I find it highly doubtful that hallucinations, if unsolved, will have any real negative effect on LLM adaptation.
[1] https://en.wikipedia.org/wiki/Computer_says_no