The major reason for suspecting long-term consequences were initially extrapolations from SARS and other related diseases. This was speculation. This was confirmed with chest x-rays in China: long-term lung scarring. People wrote this off, since it came from China. This was recently re-confirmed in Europe. Young people come off of COVID19 with reduced lung capacity.

What we should be doing is mitigating damage to those hundreds of millions of people. That's a lot easier to do than just about anything else in this equation.