To answer the question, I'll say yes EOS will disrupt steem if everything goes well as planned.
If you look at the EOS blockchain, the hype about it, its speed, the dapp running feature, etc, you'll have to say yes! EOS will dwarve steem.
But then, Steem has it's own purpose and its own advantages over EOS. If it's about the running of a decentralised social media, it definitely has the first mover advantage. We're yet to see what SMT offers too.
However, it's worthy to note that the EOS blockchain has not yet been launched even though the testnet and different dawns has been tested, so everything is just pure speculation for now.
Fingers crossed. Let's wait for EOS to be launched and for it to start performing well, then we'll all see which one is more better than the other in which aspect.