You are comparing the dirty real world with an idealized “only pay those at risk” scenario. Anyone over 35 had a pretty high death rate - as you said due to comorbities but how many of those were clearly identifiable?
Additionally, imagine the optics of “anyone fat can stay home while the rest of you have to go in to work.” How would that work in practice?
And finally, populations did not fully isolate. How much more quickly would things have soread (and overwhelmed the healthcare system) if folks just went about their business? How likely is it that the “not at risk” population (now with higher likelihood of having covid do to freer movement) would stay away from those at risk?
I’m not disagreeing with some of the ideas you put forth, but your comment comes across as absolutely certain. The world doesn’t work with that kind of certainty - we can’t all even agree on what did happen/work. Heck - lots of people don’t think the vaccine itself is necessary!
I can tell this subject frustrates you. One way to help yourself be less frustrated (and more correct!) would be to think more probabilistically and accept that all of the options are bad ones, and your preferred intervention might have been better but it also might have been worse. The world is dynamic and we don’t have any counterfactuals that we can use as comps.