Well, I don't think Steem will die because of EOS. Why would it die? As far as I'm concerned, I will be using both, Steemit and whatever EOS comes out with. Both could have positives and negatives. I think both platforms will do great.
For example, look at Facebook. It's the most used social media, but that doesn't mean there can be no others. Twitter, Youtube and so on... There's room for many platforms. One doesn't have to kill the other.