The only thing I see taking Steemit out of the race would be an unforeseen technical issue. As for people gaming the system and causing imbalances, that will never go away. It's always there in everything, not just Steemit. The greed is always with human societies. If Steemit can tolerate at least a certain amount of it there's a chance.
If someone is actually very successful then there's a problem with enviousness.
That's just another lovely human thing.
Nothing lasts forever. And nothing is perfect. That's the nature of this world.
But if we can keep this thing afloat and in the race at least for some time that'll be a real achievement.
There are higher forces at work and they tend to be just, fair and even. And when something isn't just, fair and even these higher forces have their ways of correcting the situation.
Humans have a tendency to over control everything.
To one degree or another we need to let a little magic work.