Given that 15+ year old bugs have recently been found in some much used Open Source has
I doubt that it really matters. The "Million Eye Army" is, for a number of reasons, a myth.
Reading other peoples code is difficult enough if the work in the same company and use the same naming/coding/documentation rules that you use. Reading other peoples code, even worse from multiple sources and standards, is something most people simply do not do.
There is a reason most long term stable OS software is backed by a single "big player" that sets the rules and does the major contribution. And another why "we rewrote much of it" is more common in OS projects as well.