Sigh...It looks like people still don't understand the most basic mechanics of share valuations. For a company to have a market cap of $6 trillion, it is not necessary for people to "actually put in that much money".
Let's say you have a company with a market cap of $100,000 and they have 10,000 shares trading at $10 each. But the company has finally perfected their super-duper genetically modified goose that lays golden eggs and 1 out of ten eggs is not a golden egg, but a real one that turns into another goose that lays golden eggs. Forgetting that, with enough of these geese laying golden eggs, the price of gold will eventually crash, investors start bidding up the shares of the company. But none of the 10,000 shareholders want to sell. Eventually, other investors want in so badly the bid price reaches $1 million per share and a weak hand decides to sell his/her one share to the million-dollar bidder. Now the shares are officially "worth" a million dollars each, and the company market cap is 10 billion dollars. But only one share and $1 million dollars has traded hands as the market cap has gone up by nearly $10,000,000,000.
The share price and the derived market cap are artificial constructs based on the price of the last share traded. I'm shocked that so many people still don't understand what share price and derived market cap actually means after all the good explanations that have given here in the not-so-distant past.
edit: And to be clear, even if exchanges have special rules that prevent the sale of one share from moving the price that much, the principle is still the same, the market cap is a derived metric that has nothing to do with that much money having traded hands.