I have been working on a monorepo C++ codebase with on the order of 1000 person years of development on it.
And no, we didn't have major issues with memory leaks either. About on par with what I have seen in garbage collected languages. RAII works quite good most of the time.
I take it that your project being a monorepo means you have access to the code and can change it when deemed neccessary?
I get how that would be characterized as "trivially fixable", but I assure you that this is not the kind of projects people complain about when they discuss memory safety issues.
Consider that some people need to send emails to vendor companies begging them to stop segfaulting, writing the stack or leaking memory. You're lucky if it gets fixed in a few months, because that means you wouldn't have to seek alternatives which would be even more time consuming. In conclusion, there are many people out there dealing with memory safety issues which are anything but "trivially fixable".
Microsoft and Firefox have cited around 70% memory bugs, and they probably have tooling and whatnot. There are a few languages with good C/C++ FFI that are a better choice for memory safety, and so the tradeoff there isn't very high. I grant there may be ABI edge cases or whatever, but C/C++ is no longer viable or necessary for a good portion of software.
And no, we didn't have major issues with memory leaks either. About on par with what I have seen in garbage collected languages. RAII works quite good most of the time.