Did the Dominion ever try to find out what happened to those 2800 ships they lost in the wormhole?

Could well be; I haven't seen it in a long while.

I recall a line about how only 1,500 Klingon ships were resistant to the Breen energy weapon, and that the Dominion forces thus outnumbered them 20:1. So the Alpha Quadrant force was in the region of 30,000 ships.

Now that's after a year or two of wartime production (and losses), so I can buy that the Alpha Quadrant fleet they had at the start of the war was small enough that 2,800 ships was a significant force to them.

But surely if the Alpha Quadrant fleet could be built that big that fast by the Dominion, then their home fleet back in the gamma quadrant must be absolutely colossal. Well over 100,000 ships, if not several times that.

Given that, I can't imagine that losing 2,800 ships would bother the Founders at all. It's likely a tiny fraction of what they have on hand. Given how callous they are, I imagine their first reaction would be along the lines of "Hmmm. Well, try sending another 2,800. See what happens."

 

I agree that in the long haul the loss of 2800 ships and crews was not a big deal to the Founders, the Female Founder even made some smug remark about it to Dukat, saying something like: "Well, this war will take alot longer than expected" but yes, it was no big deal in the long term. However, I don't think they had a 20 to one advantage at that point. It seemed like they only had enough ships in the AQ to hold onto what they had up to that juncture, but they NEEDED those 2800 ships to accelerate the campaign and stay on the offensive, the Klingons and Federation were probably thinning them out, they might have even been causing heavier losses to Dominion numbers in the AQ then they realized, I'm sure the Dominion threw around a lot of false intelligence and misdirection to confuse their opponents.

 

Not entirely true, by the way.

VOY had that episode about the two Ferengi in the DQ, which was a loose end from TNG. Also, being isolated in the DQ, they wouldn't have had that much opportunity to 'wrap up loose ends' from AQ affairs in the first place.
ENT had episodes exploring the Klingon forehead change.

Whether these attempts at wrapping up loose ends can be called successful is another story... but they at least tried

 

Another thing to remember about that 20 to 1 number regarding the Klingon ships toward the end of the war is that it is the combined forces of the Dominion, Cardassia and the Breen.

Cardassians have a decent enough force, and we have no idea how large the Breen military is. I think, at best, the Dominion force is about half that 30,000 number.

One other point to consider... numbers are always a good thing, but strategy is key. The fleet to retake DS9 was outnumbered two to one, yet they managed to break through the lines. This was dialogue after Sisko made it through and was heading back from the wormhole.

Even the Vorta understand how resourceful and smart Starfleet is when they say things like "One of your famed Starfleet engineers who can turn rocks into replicators."

 

The cardassians saw what happened, Weyoun saw what happened and Odo knew what happened. To them it probably wasn't worth investigating in more depth. Given how dangerous the prophets can be if I were the founders I wouldn't have wanted to provoke them.

 

All Weyoun or Odo would know is that the fleet never came out of the wormhole on the AQ side.

 

My head canon says the Founders sent in a Vorta negotiator next. The Prophets chatted with him and then altered him to no longer believe the Founders were gods. He returned to the Founders, was promptly executed, and they prohibited further use of the wormhole.

 

Gul Dukat explained to Weyoun regarding the prophets and Pah Wraiths. If Weyoun didn't believe then he did when he saw what happened. It wouldn't have been very long before the female founder and the other founders heard about it and understood not to provoke the prophets.