1. The median age of death at 79, and 50% of people have 3+ diseases doesn't imply that "Nearly all of the people who die from COVID had a life expectancy of < 1 year" as you say. Those 3+ diseases you mention include diabetes, high blood pressure, and obesity etc... Diseases that people commonly live with for decades. The median remaining lifespan of a person who dies of COVID has been estimated to be around 12 years [1,2].

2. Lets say you are correct and 90% of people who die of COVID would have died within 1 year. And let's assume that you have some magic PR method that will convince 100% of the population that this is true.

That means that COVID is still more deadly than the Flu, and some large percentage of people will still choose to remain home, stop traveling, stop eating out etc...

These people will continue to damage the economy until an effective vaccine is available. And even in your scenario a vaccine that is 95% effective will still save millions of lives.

An effective vaccine will save lives, and it will improve the economy. There is no logical reason to deny that fact.

[1] https://wellcomeopenresearch.org/articles/5-75 [2] https://www.medrxiv.org/content/10.1101/2020.06.08.20050559v...