I suspect that the marginal value of a dollar to Elon Musk is close to zero, which makes it difficult to test his sincerity in his beliefs by offering a bet.

I would structure it like this: I give him $100 right now, and if there's no AGI in 10 years, he gives me a squillion dollars, or some similarly large amount that reflects his confidence in his prediction. This way, he cannot claim that a fooming AI that renders dollars worthless will deny him the benefit of a win, because he gets to enjoy my $100 right now.

Elon is unlikely to accept this wager; would anyone like to accept it in his place?