The way he explains it, most viruses follow a similar life cycle. At first they spread slowly & are very harmful. With each variant it is able to spread faster but becomes less virulent. Eventually it is widespread, common place with minimal effects on it's host. He explained that the virus wants to be able to transmit to different hosts without harming the host. If it harms the host it is limiting it's own chances for survival. Eventually it is just another part of the host's genome. If Covid follows this pattern, there will be more frequent, but less severe variants.