Sure, the model can go wrong, but sometimes it's able to realise that and correct its course. Stronger models are better at doing this.
People do exactly the same thing! Haven't you ever wasted a lot of time chasing down a blind alley?
To say the LLM has immutable limits because it only predicts the next token and can't backtrack is like saying we have immutable limits because we can't travel backwards in time. It's a true statement but not particularly relevant or helpful.