[soperj]

This makes sense. Would also make sense why AIDS hasn't evolved to become less deadly, but it also brings up that covid hasn't had a bottleneck in terms of transmission. The main reason why one strain has replaced another has been that more recent strains are more transmissible. Delta was more deadly (and transmissible) than alpha, beta & the original strain, and came later for instance. I think we got lucky with omicron, which evolved from alpha if i'm not mistaken.