No one can say for sure but I don't think steem will ever totally collapse. I mean i don't think it will go to ten cents or whatever. It's hard to keep putting in and never cashing out, but it's also good life training. I have not seen any other site that i think will over take steem, the model here is pretty good. Things could be tweaked for sure but quitting now you would so totally regret it if the SMT's took off and became huge.
There is a long way to go in its journey and the more it decentralizes, the safer and more stable it will become. The model will work and the more it gets supported, the better it will be. People should spend less time worrying about competition and more time improving what they have.