I think the key difference is that KGLW is such a collaborative project. When everything is humming along, being prolific is great, but all it takes is for one or two members to get out of sync with the rest of the group for that cadence to fall apart. Marriage, kids, health issues...all of that life stuff places stress on the group dynamic.
I mean, maybe they'll surpass expectations. They already have; maybe they'll continue like this forever. It's not sustainable for most artists though.
I sincerely did not expect to compare & contrast Gizz & Bucket Head when I woke up this morning!