I understand "success" as "the bitcoin protocol provides a P2P payment system that does not require trust in a third-party authority".
We now know that the bitcon protocol does not provide that. The protocol requires users to trust the miners; which is OK, as long as mining power is sufficiently well distributed over thousands of independent entities, benign or short-term greedy. However, the protocol cannot prevent concentration of mining, and in fact forsters it. Once mining is concentrated in a small number of companies, having to trust them is no longer OK.
OK lets all jump on Jorge,
Jorge you're not expressing a sound understanding of Bitcoin.
Miners, in order to have a block accepted must follow the rules of the protocol.
The protocol rules are maintained by the p2p network of nodes.
Nodes are maintained by those who have an invested interest in the blockchain's integrity.
We hardly need to trust miners given the incentives, or the economic cost to participate but not cooperate. From my understand even if there were very few centralized miners the incentives would still provoke cooperation.
To your credit that balance is not well understood by the community or some of the core developers, mainly those accredited to authoring the SideChains white paper.
While it's the nodes and not the miners that maintain the features in the Bitcoin protocol, the p2p payment network and the incentives that motivate miners and keep them cooperative is successful by your definition.