So if the blockchain evolved such that it took 2 or 3 hours for a transaction to clear, and cost, say, $5,000 then during the same 2-hour block Goldman could let A sell 50,000,000 pretend bitcoins to B, B could sell 25,000,000 pretend bitcoins to C, and 25,000,000 pretend bitcoins to D, then the price could move up (or down) and A could buy back 25,000,000 from C and 25,000,000 from D, so that A, B, C, and D have the same number of virtual bitcoins that they started with - but the exchange could have resulted in a transfer of net actual dollars between A, B, C, and D - without incurring up to 50 million * $5,000 = $250 billion in transaction fees?

Where even though this net transfer happened, all of A, B, C, and D think that it was fair and what they wanted? (I call them "pretend bitcoins" because they don't need to be reflected in the blockchain - the transaction of 25 million pretend bitcoins in motion aren't reflected in the blockchain.)

feel free to correct me if I'm very wrong.