That’s exactly what I have. The C++ codebases I work on build against a specific pinned version of LLVM with many warnings (as errors) enabled, and building with a different version entails a nonzero amount of effort. Ubuntu will happily install several versions of LLVM side by side or compilation can be done in a Docker container with the correct compiler. Similarly, the TypeScript codebases I work with test against specific versions of node.js in CI and the engine field in package.json is specified. The different versions are managed via nvm. Python is the same via uv and pyproject.yaml.
I don't doubt it, but I don't think that situation is accepted as the default in C/C++ development. For the most part, I expect OSS to compile with my own clang.