ZRX itself does not depend on any single exchange, but stands to benefit from the sum of all exchanges. Likewise, all exchanges built on it benefit from access to the entire liquidity pool. Zrx network effect is strong for both investors of ZRX, and those creating and using exchanges with it. the protocol is written in such a way that it can have its cake and eat it too. Generally there are limitations to decentralized exchanges- specifically the speed at which orders can be place and executed. However, with the ZRX protocol, the orderbook can be run off-chain, with the blockchain being only used for the settlement portion of the transaction