I'm glad you mentioned that as I intentionally used only the numbers that we've been provided.

One can not apply fuzzy logic if we do not have all the numbers. I feel confident in saying the simplistic approach of flattening the curve by playing with numbers behind curtians leaves us rife for debate. The people in charge of what to spoon-feed the public are well versed in grinding numbers.
Between the blurred numbers we can only guess what is going on.

Using the 1/28th example you mentionse there is yet slightly over 493 thousand deaths to reach herd immunity. This is barring the other influences I mentioned. Using the 73% number of people that died of covid yet had preexisting conditions (but not in dire shape) equates to 133,000 healthy and 360,000 with pre-existing conditions dying to reach herd immunity
Since it's been said we have enough hospital beds, we will need more masks, body bags and test kits to go down that path.