That's plausible. The bigger constraint to defaulting to RVA23 is that users are running on, and building all of their wheels targetting, RV64GC. So unless our users adopt RVA23, it would be unwise to switch.

Great point. But QEMU is no longer faster than real hardware for the latest RISC-V chips.

You are right though that QEMU is probably faster than anything only capable of RV64GC (lacking RVA23). So QEMU would probably be a great option for the CPython team.