The reason for that level of sucess is because it does better what it proposes to do, which is to be a good store of value and censorship resistant. Most other currencies try to do the same, but there is no way for them to achieve this being so centralized.
Yet bitcoin is one of the most digital currencies that last long until now and so on, and it's special for everyone of because it is the center of market that any coin would connect by bitcoin. For now value would go down so depth but in time comes it reaches the top again and that would make bitcoin more interesting by its price value, to think bitcoin has a lot of connections in this world and many investors also with a high status. Which would help bitcoin stay strong and even it rolls up and down its still in progress for the end of the year and for me thats make sense so i much more exited for at the end of the year.