joining every social media platform there is, under just one blockchain
Very good point. The one ring to rule them all.
EOS isn't a competitor, actually. It's just a platform to let you build any app on a blockchain that scales well (but is not totally decentralised as Ethereum).
I believed EOS will eventually compete with steem. I am not sure about this, but by checking posts like this
https://steemit.com/steem/@nanzo-scoop/fd9s0t4v
I thought a competition was being formed.