Price will always depend on its popularity, based on supply and demand not its existence. I do believe that Bitcoin can last long since its till gaining popularity, still gaining users and investors. It will likely stay for a while until a new digital currency dethrones. But thats still a long way down the road. And it will not crash at a random time. If it did, there will be a rational explanation for it. It can be a discrepancy or an outside environs fucking up with it.
Yes. There seems no such sort of thing which can demolish the future of Bitcoins. But you never know what will happen next. Looking at the way how it is gaining popularity amongst investors, it will be unjust to say that Bitcoin holds a dark future. It is just a matter of time that will prove us otherwise.
Well, there is always a risk of bad things happening, like government attacks and internal conflicts involving developers and miners. However, due to its decentralized nature, it is very unlikely that governments will shut down Bitcoin.
Regarding internal conflicts, the worst thing that could happen would be another fork, in which case the market could decide which is the best.
The problem with forks is that it weakens bitcoin, a fork in any other open source project most of the time is a good thing since you get two different visions of a product, and while we get that with the forks, at the same time, that takes hash power away from bitcoin and also creates confusion among people about which coin to back with their support.