And for Linux as a plausibly community-managed meaningfully open as in open project, that clock is definitely ticking.
The end of this road is some corporate-funded retirement home for understaffed and underfunded projects once enough of the current devs have aged out without anyone growing into those roles, with private forks at companies that relied on the kernel, also privately relieved there's no need or reason to deal with antediluvian developer processes or bother giving back anymore.