> That’s why we’ve generally observed later variants of some viruses to be less fatal. It doesn’t do a virus much good to kill its host.

While this is somewhat true, there are important limitations to this model. If a virus has already done enough spreading, from an evolutionary perspective it doesn't matter much if the patient dies later. Another factor, observed in Delta variant, is that having a respiratory virus that is more contagious might also mean it is more deadly, because it is disrupting more cells to produce more viruses.

Evidence is now leaning towards the possibility that it came from an immunocompromised person who had a very long infection - https://pubmed.ncbi.nlm.nih.gov/35739343/

Delta is not the ancestor of Omicron. Delta did not "evolve into" Omicron — it doesn't even have alpha variant in its lineage.

Another way this analogy breaks down is that humans have sexual reproduction whereas viruses are almost entirely asexual (with rare gene transfer exceptions). Neanderthal genes can enter humans because they are sexually compatible, but viruses have to rely on convergent evolution.

The game resurged in popularity in 2019 due to the combination of well-received updates and popular livestreamers. It's retained a good chunk of this popularity ever since.