Steemit is almost certain to carry EOS to success if Steemit sticks with EOS.
The reason is that anyone can easily make content on Steemit with good chances to be rewarded once one is known a bit. Plus there are quite some members on Steemit already that are interesting enough to keep people involved.
As it stands currently, Steemit sails just by itself nicely. The owner would have to shut it down out of bad mood. As long as that does not happen, there is no hurdle i can see.
There isn't really one owner of steemit who can shut it down because of a bad mood. The idea of Proof of Stake means we all have ownership and it gets it's increased value from people believing in it's value. So it's in all steemer's best interest to make this the best social network in the world.