More than most people seem to think. There's the never ending infighting, the possibility of a fatal flaw, many of the businesses and exchanges aint professional enough, alts might keep on growing, authorities might start cracking down.
That's why there's basically no one here still and why there might be serious growth but don't let anyone tell you it isn't a gamble because that's what it is.
Not sure what you mean by there being no-one here, looking around on the forum there's still a fair amount of people and I haven't been seeing any mass exoduses, even a trickle of users away from the community doesn't seem like a major concern right now. While the market might be a bit of a gamble, it does have some trends that it follows and it isn't impossible to predict movements, just a bit more of a challenge with whales and everything.
Maybe old users of Bitcoin are leaving, but the community seems really vibrant for what it is. I could be wrong.