What made bitcoin survive is that it is decentralized. There is no central point which can be attacked and shut down.
Past attempts to create a digital currency all failed because they were not decentralized and/or because they couldn't solve double spending.
Bitcoin is the first peer-to-peer digital currency. Bitcoin is the first truly decentralized digital currency.
Bitcoin is super successful today because of these two things: A peer-to-peer network, and decentralization.