Exactly. I've been trying to hammer this home to anyone that will listen (and occasionally even those that won't). It doesn't help that some of them are religious and inherently dubious about evolution, regardless of the actual science.
Maybe the next iteration will be less contagious and more deadly, therefore more effective at wiping out the deniers.
But that would fly in the face of evolutionary theory - things that kill their hosts tend not to last long.
Less contagious is unlikely for that reason - a less contagious strain will be swamped by its more contagious cousins.
But deadly viruses don't last long because all the hosts are dead. A highly deadly and highly contagious disease with a long infectious period before symptoms develop is quite capable of killing a sizeable fraction of humanity before the death toll causes it to run out of hosts.
The 1348 pandemic killed about a third of the population of Europe. Perhaps more. Some cities had 90%+ mortality rates.
Disagree--a truly deadly virus can burn a population to the ground by not being so deadly in some other host. The Black Death was such an example--the bloodsuckers that carried it had a short enough life cycle that it wasn't going to wipe them out.