That was a temporary experiment to see if more people enabled Grant to produce more videos, but the Mythical Man-Month rang true again. It's just Grant now, like it was when it started.
I didn't realize that happened. Kind of a shame. But he did get that interactive page for visualizing quaternions built with a collaborator.
He's still experimenting with different approaches, trying to find the optimal flow like any startup would. His approach as of late has been to collaborate more with other channels, like he did on the Feynman video and the interative quaternion page you referenced above.