But that's the point: the original poster pointed out the great value in store-and-forward, latency-tolerant systems like email. So while you may indeed be luck

But that's the point: the original poster pointed out the great value in store-and-forward, latency-tolerant systems like email. So while you may indeed be lucky and have low-latency interactions through email in certain situations, you've then added extra assumptions and requirements to the aforementioned latency-tolerant robust system. Wanting fast ("instant") response times from a system based on email seems like a folly.