That surprised me.
And yet, it also didn't.
From what I know of him, which is just from watching videos, he doesn't seem ideally suited to the day to day grind, and detail, of managing a medium-and-growing company. And LMG has grown large enough that those day-to-day issues, not least personnel issues, could be one heck of a burden.
So his "standing down" video seems to suggest he's handing off that management role to a proper "manager", but staying on for the creative and "vision" role, a bit like a cross between a creative director and a non-executive chairman. Nothing much else, including apparently, the company ownership, is changing - he and Yvonne still own it outright.
So all in all, I find myself surprised, yet not that surprised.