I think it depends on what kind of OSP they are.

For example, Linux kernel is definitely widely used and I'd argue that it is one of the few things that have achieved globally acknowledgement and usage, i.e. a "human" thing, as the aliens said. Such a project would naturally require some strong leader (Linus is famous for being straightforward and none-BS) and a bunch of able enforcers (maintainers). I don't think we are short of able enforcers, although the total number of Linux maintainers who understand the full picture may be small, but we don't need a lot of them anyway. The key is to elect an equally good and strong leader, without which the project may degrade slowly, like all human projects. I'd hope someone with both the technical knowledge as well a strong character to take over whence Linus retires -- but Linus is only 55 years old so I believe he and the community still have many years to search for the next leader.