It's really not. What Elon says is whatever is currently floating in his head or whatever he thinks will give him a stock boost.
He's not credible with respect to his companies plans. It's happened like dozens of times when he says something well or will not happen, and it turns out he was just lying.
The default stance of reading Elon today has to be, "this is probably a lie. Put no value in it until it is proven true".
Reuters claimed multiple sources and documents from project managers telling workers to wrap up the project and document it for "lessons learned." I tend to assume on a story of this importance Reuters is operating in good faith and the quotes from those documents aren't fabricated by the reporters. And those quotes seem pretty definitive.
This doesn't mean the reporters understood everything. Musk could easily have disputed the reporting by providing that extra context (e.g., "we changed the project name, Reuters is simply taking some isolated emails out of context") but he chose not to do that. I'm generally open to the idea that Reuters got something wrong, but the claim here isn't that: I'd have to believe that Musk is credible and Reuters is deliberately lying.