I don't know, I kind of feel like bitcoin is the Yahoo of digital currency, It works, it's popular, and people have used it since the birth of this movement. But sooner or later the google of digital currency is going to come along with a vastly improved way of doing it and leave bitcoin in the dust. I don't think that's happened yet or is even about to happen, but these things happen all the time in tech. Friendster > MySpace > Facebook is another example. One dominates till something better you never knew you wanted comes along.
Keep in mind I'm not an expert by any means, who knows what will happen? If anyone did know I'm imagine they would become very rich.