It's easy to forget that there are still quite a few power players who could essentially "Buy bitcoin" and take a huge huge share of it.
Or satoshi could reappear, for good or for evil, and tank the whole thing.
We're far from "stable" on a macro, global scale... it's still cutting edge tech in my eyes.
Someone could take over Steemit if they could find enough available Steem. It's a risk, but I hope it becomes too big for that soon. We already have enough whales, but I'm grateful enough when they decide to vote for me.