Actually, I don't think that's entirely accurate. I think it's that Jimm wants to have it done his way and only when he's ready. It's not like a lack of potential manpower or professionalism of talent or anything.
I'm not belittling the time or effort put in by the Exeter crew. Far from it.
I'm just pointing out the tremendous advantage NV/P2 has in having so many people with real industry credentials and experience working on it. They also have a big advantage in resources, particularly in the FX department having have NEO to do their CG work.
Exeter is being done in homes and garages by people who are learning as they go, and don't have the advantage of deep pockets backers (resources, not necessarily cash) to help them along.
It makes Exeter's end result all the more impressive.