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.
A lot of people have asked why Bitcoin has a higher price than other currencies. I think this depends and the level of profitable the supply and development platform. Bitcoin is currently the market leader in the highest rate and this may be a long time in the future.