Ok I don't think steemit will fail or close for any reason. Steemit is just getting started and just look at how much traction the site has already and it's ace in the whole which is the SMTs hasn't even been launched yet.
Have you taken a look at the number of Dapps that are available on the steem Blockchain?? Everything from dtube to musing and all the others are so good that they could even give sites like YouTube and Quora a run for their money.
The world is gradually moving to the blockchain and seeing how accommodative the steem Blockchain is I'm pretty sure when the SMTs are released the whole world will want a piece of steemit. These new sites like weku and the others are simply just imitations of the real thing and although they're on the right track, they still have a long way to go.
Steemit isn't going anywhere except for to the moon!!!!