Even though Paramount and UPN were owned by the same parent company, they were -- as is standard practice -- run and treated as two separate business entities. You can find evidence of this during the discussions of the final season of Enterprise, when the show got to stay on the air because Paramount agreed to accept a reduced licensing fee for the show from UPN. It wasn't all just looked at as one big pile of collective money, or else there would have been no reason for UPN to pay licensing fees to Paramount.Exactly!!
Also what some overlook is that while DS9 had higher viewership, syndication wasn't paying as much as a major network. What's the point in being higher watched if you don't gain anything from it? Having all those folks watching is nothing if you aren't making major network profit in syndication. Voyager stood to make more being on Paramount's UPN because it was their own network, the money they put into it went back into their own pockets. There was no third party involved in UPN to dictate how much they'd get paid back for their show.
My point in saying that is that we really don't know whether the syndication packages for TNG and DS9 paid more or less vs. being on UPN. True, Paramount got licensing fees from UPN for the show, but then UPN got all the revenue from selling the commercials. In the syndication format, there weren't those licensing fees coming in, but Paramount sold the commercial time to advertisers directly and received all that income. Which made them more money? I have no idea, because I don't have access to Paramount's books. But it's certainly not just a given that dealing with UPN made them more money.
Regardless, the notion that has been presented in this thread that TNG and DS9 didn't make Paramount money because they weren't on a major network is simply ludicrous on its face. Paramount is not a charity. They didn't produce Star Trek just because people wanted them to. They did it, from day one, to make money. Had TNG not been profitable, they would not have continued producing it for seven seasons, and they sure as heck wouldn't have then created a spinoff series in the same syndicated arrangement, and run it for an additional seven seasons.