Damn sir, that’s lots of words and a metric shitload of syllables. I think I get the gist of it. As always, I appreciate ya. A lot. Thank you sincerely.Yep, the time scale for lesser virulence to dominate an evolutionary landscape can be significant. Retroviral endogenization took millions of years (in classically studied examples) and it occurs over the course of an evolutionary arms race with host responses. Fast killing viruses are disfavored as they self limit their spread (and often the host is obviously sick so other potential hosts know to be careful).
This virus is like a tuned down SARS-CoV which helps expand its reach. It comes from the same reservoir of bats, and appears to have picked up sequences from a coronavirus in pangolins. Symptoms don't manifest immediately and it kills less than SARS-CoV, in or above the range of the deadly pandemic flu many have feared would eventually hit the world again.
For SARS-CoV-2 to be outcompeted by a less virulent form, a less virulent form would have to emerge that spreads more efficiently and potentially gives direct infection resistance to SARS-CoV-2 or induces a crossneutralizing immune response. Otherwise there's nothing to make the more pathogenic form disappear. Alternatively, SARS-CoV-2 has to sweep the planet and kill so many hosts that it starts limiting its own spread and a less pathogenic form is more successful in spreading because it doesn't eliminate its host pool. These things take time and significant carnage.
With flu, we've been vaccinating against H1N1 for years. We are inducing the selective tools in our bodies to limit the virus's spread.
Don’t forget us uns in the slow crowd...