But until Dax and Sisko discovered the wormhole the orbs proved nothing - even the Orb of Time would rely on people's testimony.
D'oh. It's an excellent point that the discovery of the wormhole was revolutionary, although I wouldn't say the orbs proved literally nothing. Also, to a "doubter", all the wormhole was was a wormhole, albeit a stable one, so it didn't really make any religious interpretation of the orbs more convincing than it already was.
I think "miracles" like being aware of the other timeline in Accession
get at least as much mileage for proof of the Prophets as the wormhole itself does.