In my experience his influence was strong but well delegated. The culture and leadership of the company was more important, and would live on without him. There are a lot of people who were attracted to Patagonia because of the way it was run, and the reason it existed, and they want to see it continue with the same focus. It's not perfect (and neither is Yvon, of course), but it seems to be on solid footing, and I expect it to be even after he leaves.