That has been my feeling about them. They were maybe a limited run. Hard to say how many of the few made survived the Dominion War, obviously there was at least one loss. With the experiment of families on board abandoned, they still could have had good uses as haulers, evacuation ships, etc, but perhaps they had been best as test platforms for technologies that would be utilized in other ways after the Dominion War and Borg incursions.
Or maybe they're kept in a reserve fleet now converted to something like the three nacelle variant seen in that alternate timeline, and since they are battleships and no longer science vessles, Starfleet just doesn't show them off. I like that idea better, somehow.