Actually, it's not a problem at all. If EOS is pretty successful, steem could launch itself on EOS.
It's like this:
I built an app with some homegrown tools. Then webpack and react works pretty well. So, I changed my app to use them.
What matter is the steem community and what it does. If someone could do it better than steem, that's also good thing.
It's like we've twitter, facebook and many other social networks.
It's only not a problem if we recognise the issue, work out if it is one and plan! :) Things move very quickly in this space. I don't believe we can afford to rest on our present advantage. I think we should drive it home.