I have heard this as well, however I have to wonder, once it became apparent that the network restrictions made Voyager's premise unworkable in any meaningful sense, why not retool it into something more like TNG. At the end of Season 1, they could have found a stable wormhole / transwarp drive / pick your own plot device, which brings them home. Season 2 they are sent back out by Starfleet via the same means to conduct further exploration. Same show and all you lose are the marooned far from home and limited resource elements that were frequently glossed over in the show anyway.
Maybe it's because once they defined it as a "quest" show, it was subject to the usual television logic that if the quest is fulfilled, the show is over. "Will they ever get home?" was the hook to grab the audience, but UPN didn't want to deal too much with the ramifications of that question.
I don't know, though. The creators' original intention, according to their interviews at the time, was never to have the quest for home be the dominant element of the show; their desire was to get back to the flavor of TOS where the ship and crew were completely on their own without a Starfleet Command to call for backup, and stranding them on the other side of the galaxy was just supposed to be the means to that end. They intended to move away from the "oh, how do we get home?" stuff before long and have the crew embrace the wonders of the Delta Quadrant. Yet for some reason, it wasn't until season 3 that they really committed to making that transition; after "False Profits" near the start of season 3, we didn't see another quest-for-home story for nearly the remainder of the year. But then they did "Scorpion," in which Janeway made an insane deal with the devil in order to get closer to home, and that solidified the quest for home as the single overriding priority of the ship's mission and the series' premise. From that point on, it could never be about anything but the quest for home. So for whatever reason, the producers changed their minds, or had it changed for them, about what the focus of the show should be.
The one downside I could see is that this altered premise would allow writers to incorporate more elements and state of affairs of the rest of the Federation, which may have constrained the writers of DS9. DS9 among other things, had the advantage of pretty much having the entire sandbox to themselves once TNG went of the air. Since Voyager was away in the Delta Quadrant and (for a good while) out of contact, nothing the writers did on that show would really impact DS9.
That's probably a major part of it. Since DS9 was syndicated and VGR on a network, there might've been a desire to minimize crossover elements. Recall how Buffy
crossed over heavily when they were on the same network, but when Buffy
switched networks, the crossovers mostly ceased.
Tangent, but still related to the OP, I've always felt TNG would have worked as a revolving door "Law & Order" style show. Just rotate in new cast members as older ones want to depart. Promote Riker to Captain. Give Data his own ship. Promote LaForge. Transfer Worf. The drama becomes more about the mission, which TNG kind of already had going for it.
I think they considered it once or twice. And yeah, it could've worked -- and would've made a lot more sense than having the same crew stay together on the same ship for a decade or three.