OP, please delete, lock, or throw this thread into oblivion.
Even if I don't like much Polo lately and it may have troubles, your theory is completely wrong.
1. Trading doesn't mean buying. It can be traded in any direction.
2. Trading on Bitcoin market means the sum of bitcoin and altcoin trades. And, although it would be useless (see point 1) you didn't add the altcoin wallets to the sum.
3. You totally missed the cold wallets which any smart exchange would use on a large scale.

So again, bury this thread, you just scare the less experienced people away from trading.