Many people don't realize just how conservative C++ is (the OP only briefly mentions this). The committee not only avoids breaking existing source code, but eve

Many people don't realize just how conservative C++ is (the OP only briefly mentions this). The committee not only avoids breaking existing source code, but even binaries, although binary compatibility is not defined in the standard at all. C++ 11, 14, 17, 20, and 23 are all binary compatible (modulo some possible oversights). There are many quality-of-life improvements that got voted out because then a binary compiled in C++11 wouldn't be compatible with one built in C++23 anymore. As a simple example ([1] has many more): the only reason we have both std::scoped_lock and std::lock_guard is because changing the definition of the latter would have required re-compilation of existing code, so a new class had to be introduced. ABI stability even overrides performance in committee decisions (see the std::regex example, but I also heard it affects the footprint of unique_ptr - edit: found it [2]). tl;dr breaking source code compatibility seems way off if implementors don't even dare to break binary compatibility. [1] http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2020/p2028r0.pdf http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2020/p202...