There is no need to imagine, we have the forecasts from the Imperial College report:

https://www.imperial.ac.uk/media/imperial-college/medicine/s...

There are 40 million 40-somethings in the USA, you're proposing that 100% of them will have lung damage.

Let's imagine that 80% of the population is infected, that 80% of cases are symptomatic, and that 80% of the 4.90% of hospitalised cases (this 4.90 is direct from the report) get damaged lungs. This is one million 40-somethings, not the entire population.

1 million sounds like a lot, but its only 2.5% of the population at that age range, and assume worst-case.

You know what causes reduced lung functionality in adults? Asthma, driven by air pollution from vehicles and coal power plants. 7.7% of adults have Asthma. Where is the war-scale drive to eliminate fossil-fueled vehicles and power generation?