Capital != wealth. Capital is just how we organize labor. Wealth is what is created by the labor, the cars, the rockets, the satellites.
Elon is a manger of labor. The capital is worth $1 because the expectation that in the future the wealth created by the labor his company organizes is $1T more then the total cost of all the resources spent to do it. He gets the capital, the consumers, get the wealth.
if we had 500 more trillionaires, all else equal, it would mean the world will produce twice as much wealth as exists today. So we would consume twice as much wealth as today. So we all would average be twice as wealthy.