Ryat basically said it. They don't make money. Actually, I think Stardock might have lost a bit. It saddens me, but I don't think that the collector's editions were a profitable venture for them in the slightest.
Plus, they had to completely redo their system for selling the collector's editions just to get rid of them.
When they did the redo, I think they had around 2,100 out of 2,600 collector's editions left to sell. Since then, I don't know how many of the collector's editions have sold in their respective packages. I hope they have manged to sell a lot of them, because I would love a Sins 2 collector's edition.
That said, I think that the Rebellion collector's edition was amazing and I thank the people at Stardock and Ironclad for making it happen. And I especially thank Yarlen.
I would also be open for them making more models of the capital ships and titans. I would love a Discord, Rankulas, Sova, Dunov, Progenitor or Antorak capital model. Or maybe make a bigger ( 1 and a half feet instead of 8 inches) titan model of the every one of the titans. I would buy every model that came out. And maybe put some frigates and corvettes alongside them on tiny clear plastic sticks coming out of the side, to give them scale?
Though I think it EXTREMELY unlikely at this point in time.