If I measured by the standards I have for myself, then I would agree he overpromises and underdelivers.
Compared to the marketing bluster I see from the old aerospace companies and greenwashing from older car companies, however, heβs a spectacular breath of fresh air with his honesty, openness, and willingness to say things have a less than 100% chance of success.
And I say that despite agreeing with you about Hyperloop and TBC.
Most of his ideas aren't even something anyone should deliver. Hyperloop and Boring Company are terrible ideas.
Meanwhile everything else is over-promise/under-deliver.