Also it depends on where you start. Going from million to billion in price is currently pretty possible. Billion to trillion would be rare, but still could happen. Now from trillion to quadrillion. How much currency there is again...

A trillion dollar valuation doesn't imply there's actually a trillion dollars there. It's just the last price the stock sold for, times the shares in existence.

If Elon tried to sell every share of Tesla tomorrow, he would get a lot less than the face value of all his shares.

So in other words, there doesn't need to be that much currency, just that much hype.