The evidence lies in the failure of the cryptographic community to provide a solution with strong security properties that is performant. For example, nobody ha

The evidence lies in the failure of the cryptographic community to provide a solution with strong security properties that is performant. For example, nobody has even attempted an ORAM-based database system. We also do not have schemes that can efficiently provide an intermediate level of security, between "weak" and "strong" systems. Either way, as I said earlier, it's a question of threat models. Most cloud users trust Google and Amazon. These companies also have strong intrusion detection capabilities, so with non-negligible probability an outside attacker would be detected within a reasonable amount of time. In such a scenario, it is better to have some protection than none at all.