It's not an admission of failure. Two businessmen created one of the most successful, influencial businesses ever and are passing the torch. They're rich AF and probably want to retire.
Sure, I wouldn't disappear completely, but I'd work on low-stress things where I have a lot of free time and don't have so much responsibility under me.
Or children ;) John Lennon famously quit music for 5 years to raise his second child, after failing his first marriage.
I guess only time will tell how much I like this arrangement, but I'm pretty optimistic about it, and am tired of hearing the usual "oh but you'll be bored and want to work again" tropes. There's a lot more to life than work...