Will bitcoin eventually rise or it will fail and reach a value of zero dollars?
There is no chance of lowering of prices. but if you are a smart investor, then you should keep an eye on the fluctuation of prices.
I think bitcoin will not reach a zero dollar for a couple next years, but no one know the future.
Just follow the trend and do technical analysis is the best way to predict bitcoin price.
I don't think it will reach zero dollars ever at this point. It is pretty much the "gold" of digital currency. So far there is not another that is going take over.
Even if one takes over one day I think BTC would always be a alt coin in worse case. We are still very early with with digital currency so anything could happen I guess.