Probably accurate for active professionals in the big three countries, and probably a bit generous. I doubt there are many professionals, if any, who need three

Probably accurate for active professionals in the big three countries, and probably a bit generous. I doubt there are many professionals, if any, who need three stones against the best. In fact, top western amateurs might be competitive on three stones. There has been some compression of professional strength in the past 50 years, so there may be some older professionals who need that much. Additionally, there are players with professional ranks who no longer compete, or only compete in Western tournaments. They may need three stones.