The whole idea of a centralized market, with someone syphoning off large amounts of money and being the major legal target, sets it up for failing. Once it becomes a distributed marketplace with all services replicated it becomes much more secure.
DHTs are susceptible to Sybil attacks. A key/value store based on a cryptocurrency would be a better approach if you're looking for a decentralized key/value store that guarantees that the data is available.
