This is my opinion:
Crypto-currency isn't made to be controlled. XRP and NEM maybe but I don't consider them "crypto-currency" because they're "THE BANKS COIN". You have to consider coins like Monero or Bitcoin and the purpose of owning decentralized money. I don't think the banks could control this if they wanted to. With XRP and NEM, I think banks are trying to cash-in the technological benefits of blockchain but not try to "win the game". So, the future for XRP is great as long as people use banks but i dont think it has market dominance potential. I heard somewhere that the coins aren't fighting for dominance but finding a way to exist symbiotically with another.

You can't control something inherently uncontrollable. Hope that helps!