Perhaps so, but the synchronization primitives leak out eventually, e.g. while profiling or debugging. Semaphores also exist in other contexts, like POSIX/IPC,

Perhaps so, but the synchronization primitives leak out eventually, e.g. while profiling or debugging. Semaphores also exist in other contexts, like POSIX/IPC, distributed semaphores etc. Even if you did manage to avoid them entirely, it would suggest a lack of curiosity if you've never looked into how concurrency is implemented beneath the surface.