It doesn't take more than engineers to maintain an open-source browser, though. Why does it have to be a company at all? Remember Firefox? Firefox was literally just an act-of-love fork from some engineers from a dead acquisition by a dying dot-com era behemoth.

Put another way, does the Linux kernel or the Python language need to be run by a company, or will foundations does these jobs ok?

There are plenty of open source projects that are enormously successful without a single lawyer or project manager in sight.