There are no very expensive vehicles or dining choices when you’re worth tens of billions. It’s literally meaningless, like it would be for me if all my meals for a year cost me 1% of a penny.
Also, since we're talking about what's "verifiably true", do you have any proof that he even had a margin call?
But almost all of Elon's wealth is in the form of his stock holdings, and stocks fluctuate in price. Moreover, his cash is almost all leveraged from his stock, and if the price collapses again, he could be wiped out by the margin call.
Depending on the advance rate (the 60% in this case), someone will do that deal.
To take it to the absurd. If Elon wanted to fund his $35M daily party habit in the comment above, and he said to a bank "here is 3 billion in stock as pledged collateral which you can sell when the value goes to $500M but there's no recourse. Cool? Cool. " You would do that deal.
So the margin call concept does not seem realistic.