Why "must" they eventually be revealed?
They do remain secret till revealed. Technically, if anyone else is told or shown what was unknown by anyone else, they're already non-secret.
I think that indicating that a secret exists, even without revealing it, ruins it. In fact, if someone implies there is something which isn't being revealed, that stirs much speculation which surely may be cause the "secret" to be judged more or worse that whatever the secret really IS!