I don't know if we have many people here that are in management at Paramount and can say exactly what is going on! Even if there is, they're probably not supposed to say anything. I don't work there, so all I can give are guesses.
We did just see a pretty major change with Skydance acquiring Paramount. They announced Starfleet Academy somewhere back in 2023, before the merger deal was made, and no new shows were announced after that. There's a chance they didn't want to start on any new shows before the transition was completed, as the new management could have a different direction they want to go.
Another option is that they've seen what many other streamers have been realizing, that the current streaming model is not sustainable, and they're not committing to any more high budget streaming shows until they come up with a workable solution.
There's also just a chance that they just haven't seen a pitch they're willing to fully commit to yet! We've seen several people talk about shows they've tried to get going, but no official announcements.