EOS is still in development and is more of a competitor to Ethereum, the apps built on top of it will require further development also. Bitshares has been established for years and unlike other "Decentralized Exchanges" coughWAVEScough it has the smart contract derivatives (BitUSD, BitCNY, BitBTC) that manage collateral, meaning you don't have to trust a third party to remain accountable.

If (or should I say when) USDT or another major exchange collapses then more people will educate themselves about decentralized exchanges and smart contract driven options. There is nothing stopping these measures being implemented within Eth and the localethereum exchange has partially done this by allowing clients to manage the private keys of wallets used by the exchange (the exchange can't run away with your coins and you can still extract coins used on the exchange even if the site goes down). I think WAVES also announced that they want to implement smart contract options.. Bitshares is doing all this already, it's up to us to add liquidity.