This disease map has Coronavirus where it belongs IMO, and also gives some perspective just how it stacks up against other diseases pre vaccines. It aint measles, and it aint smallpox, and it aint Ebola. But it is A LOT more deadly and debilitating than flu.
What we don't know that could make it worse is how long immunity lasts or whether there is long term complications, especially following mild illness.
If this was an endemic disease chances are very high we would all just get it as kids, it wouldn't even be that bad for most, and we would have some level of immunity through our lives so that it was never a problem, until maybe you get old and your immune system starts dysfuncitoning. Noone would be having their first exposure at 40+ years of age the way we are now.
I don't know for sure this is how it would play out if it was endemic, but I think there is a fairly high likelihood.
