I haven't read through everything on this long thread, but I did see this touched upon. Sometimes in software engineering when you see the nuts and bolts of something and get it working, you don't really want to partake of the finished product. You need a break from it. So it's possible he wants to go to it when he's had a break and can enjoy it like a user and not a developer.

He's also a very busy man. He may just not have time. And there's also the possibility that this isn't content that interests him much, but just because something doesn't personally interest a developer doesn't mean they can't go into the development intending to make it good. I certainly am not personally interested in every single thing I code, but I go into the project intending to code it well and make it something the user will be happy with. If it's not his personal cup of tea, then I would think he relied on others who do enjoy this content for design advice and feedback.

And finally, the idea of the lead developer partaking of what he wants on his personal account and not engaging as much with something that may not be to his interests fits entirely in the way he encourages the players to experience the game and do the content they find the most enjoyable.