I doubt it would actually kill all of humanity and make us extinct. It mainly kills the old. If 100% of everyone caught it, it would suck but we'd survive. That probably will happen eventually but scientists and doctors want to postpone that so hospitals are not all hit at once. People think that sounds like a lie since hospitals aren't full now and are laying people off but it would make sense they don't need all the admin people and nurses that aren't trained to deal with infectious diseases. I worked at a hos[pital and I know most of them are clueless and should have been laid off anyway. For covid they only need doctors and licensed nurses, not the lower tier ones who just wipe asses.
Looking at a lot of MSM sources it seems like they say the worst case scenario is this lockdown lasts two years. Such as wmd says: https://www.webmd.com/lung/news/20200504/two-more-years-of-covid-19-pandemic-likely
I keep thinking of how HIV never got a vaccine. What if it is impossible. Does that mean we have to social distance and wear masks forever? No more concerts or live sports ever? Could that be the worst case scenario? This says: https://www.bloomberg.com/opinion/articles/2020-05-06/america-has-no-plan-for-the-worst-case-scenario-on-covid-19
This is an opinion piece, but it seems most people don't want to discuss this, I wonder how likely it is. The making of a vaccine seems secretive. They should interview the scientists working on it, get more info on why that one recently failed.
Just random thoughts. Kind of a scary topic.