You can't just "assemble a new team" for that, especially with something like Spore. The developers who made Spore what it is today are long gone, and along with them went the passion for the project. It is likely no new developers would have the same drive or motivation to give it their all, and you would end up with a half baked attempt at a Spore successor, much like Darkspore. Plus, new developers would have to learn how the code for the engine and the game works, and without any of the original team that made it, it's much more difficult. Either that, or they would redo the entire engine from ground up, which would be far too large of an undertaking to be realistically possible.
Now with that, consider this, where would you be getting the new team members from? You would have to pull them from other existing projects, which is not going to happen especially as there is a small financial incentive to move members away from a larger game like the sims or their other IPs to a game like Spore.
All in all, assembling an entire team just to make a successor to a dying franchise is too large of an undertaking and is unlikely to be worth it in the end.