Which means either that their codebase is less than a decade old, or there were serious rewrites involved. Which fits my initial statement: historically, long term (T > 10 years), successful projects should have better used C++ as C-like as possible (or just used C).

I'm not claiming it's not possible to have successful projects using C++ lasting long, just that it would be, long-term (really long term), less overhead to use C for big projects.

Êdit: My personal bias: I was involved in two long-lasting projects, where just dealing with boost dependencies used up more maintenance time than it would have been needed for experienced developers to develop the code which didn't depend on boost. But of course, those who used boost didn't have such an experience to make such calls, and in initial development "look how fast we have a feature x" wins.

I personally consider Google's C++ style guide limiting Boost use as one of the best examples of some influence of some experienced developers on the policies.