Yes, if your JavaScript engine is written in C++, it’s going to be very hard to avoid very gross bugs. We have better options now.
The ability of adversaries to find and exploit very gross bugs in C++ codebases should have already compelled the industry to move to memory safety. Now that AI has democratized the ability to scour C++ codebases for really gross and exploitable bugs, I should think that our hands are at last being forced. I’m not impressed by what I’ve seen in the industry with respect to taking memory safety seriously.