You're right that a smaller percentage of people diagnosed with Covid-19 are dying, and some of that is likely because of better treatment (but there's no hard data on this yet) but it's also due in part, perhaps in large part, to the fact that early on the virus ripped through nursing homes, and since then a higher % of new infections have been among younger people, who can still die from Covid but are at lower risk. So the idea that "most recover quickly" is no more or less true, to any significant degree, than earlier on. All this is evinced by the fact that deaths are rising again, and given the lag time, we don't know how much. I do hope that treatments play a big role in shortening hospital stays and reducing deaths — we shall see.