It is very likely GRIN received the full development budget plus some margin paid on a milestone basis across the length of the project. That budget would have had some margin baked into it, so GRIN would likely have made some money on the development with some possibility of royalties on the back end.
It is possible before release there may have been an expectation of rolling on to sequel or derivative products, but with the apparent low sales those opportunities if they existed will have disappeared leaving them with spare teams. Royalty payouts would be unlikely.
And in this environment, there are not a lot of licensed projects floating around that haven't been placed, and those that are available are hotly contested. Not an easy time to place spare teams in a hurry.
It is possible this was a factor also.
All speculation of course. There could be many factors at work here and the full story is certainly not known.
