// The notion that Covid would not destroy the human race because it would not wish to destroy its hosts is, frankly, nonsense. //
I'm not sure if this was addressed to me or not, but, if so, it's a misunderstanding of my point. It's common shorthand in, for example, evolution discussions to give agency to things that do not have agency, viz. for example, "Giraffes evolved long necks to easier reach leaves on tall trees." Clearly, the giraffes actually had no say in the process, and what is actually meant is something closer to "giraffes with longer necks were preferentially selected for over numerous generations, while those with shorter necks were unable to compete successfully."
It's the same here. A virus indeed has no "desire" in any way whatsoever, but it stands to reason that an organism that relies on spreading from host to host, but kills its hosts too quickly to achieve this, will be out-competed by varieties that are less deadly but more easily spreadable. This may in part explain why, so far, the mutations observed in Covid haven't significantly* increased the fatality rate, but do appear to have increased its ability to spread from person to person and its ability to infect people once inside the body. The latter is a useful trait; the former is not.