Generally speaking it’s better for the virus to not kill the host, yes. Covid isn’t lethal enough to burn itself out rapidly, but one can imagine that the R0 wo

Generally speaking it’s better for the virus to not kill the host, yes. Covid isn’t lethal enough to burn itself out rapidly, but one can imagine that the R0 would be a smidge higher if it was less lethal, since all those dead people could’ve spread it just a bit more if they’d lived. But it doesn’t appear like Covid is the absolute Max lethality possible for a pandemic; the 1918 flu pandemic seems to indicate that a virus can have a higher CFR and not burn out. So it could certainly get worse, but in general the trend is towards being less lethal making viruses more fit.