There are a lot of reasons. First, we instantly gained access to the Star Control franchise which lets us begin creating a multiverse. Now, if there had been no Star Control 3 and Star Control 2 wasn’t 25 years ago then it would make total sense to just continue using that IP.
Ford and Reiche own the IP. We only have a license to it. While we could have used the aliens, by not using it, we leave the door open for them to come back and continue a canon sequel to the Ur-Quan Masters.
I love the characters and setting of Star Control 1 and 2 (let’s not talk about 3). But we didn’t acquire the Star Control rights to access the aliens for the aforementioned reasons. We acquired them so that we could create a new Star Control game. Plus, Stardock, unlike say Accolade, would absolutely permit an independent Ur-Quan sequel by Paul and Fred. Will that ever happen? Maybe or maybe not but at least the door is now open.
From a long-term point of view, we want to establish Star Control as the origin point for endless adventures to other universes starting with the official one in Origins. So picture your favorite but possibly neglected sci-fi universe and imagine officially sanctioned adventures in those universes.