As far as Elon goes, I think he's trying to find a distraction for Tesla's massive production issues. He seems mentally unstable and has a strong need for approval. I believe the sub was his way of trying to get people to worship him again.

I saw a comment about the caves being used by cartels on Reddit. It doesn't really make sense given that one of the lead rescuers was a civilian and cave diving enthusiast who had explored this particular cave many times. He specifically called out Elon on his sub and doesn't seem like the type who would keep his silence if this were the case.

It's more likely the MSM were freaking out that none of their FF's were working and latched onto this story 24/7 to cover up something else.