Your example doesn't makes sense to me. If there was no GIL then you'd still need a dispatch thread. And if that thread took 2% of the same compute then you're

Your example doesn't makes sense to me. If there was no GIL then you'd still need a dispatch thread. And if that thread took 2% of the same compute then you're out of luck. The lack of a GIL doesn't magically distribute compute across many CPUs. You could off course make a minimal dispatch thread and then offload the 2% to other threads but you can do that with a minimal dispatch process as well.