Hmm, you are quite positive about all this, I like that : )

But what you said is kinda true, if people still keep using steem (posting and all that) then steem most likely won't die and will actually have a future. I guess the problem is, that people do give up. What happens if the witnesses leave because it's just too costly and not self-sustaining? So yeah, it is like how you said it is. If people give up then steem dies, if they don't give up and stay with steem, then it won't die.

Still, there's always that chance that something new and better will come along, which will make people leave/give up steem and just join that other thing. We'll see.

(We gotta admit, steem currently is definitely not as great as it could be, not yet at least...)