Muller’s Ratchet
Nature is set up for maximizing survival. A virus lifecycle is designed to become more transmissible and less lethal. This is all viruses, since the beginning. This is how they work
More spreadable, less serious. This is why they say symptoms appear like Hay fever. How many lives are lost each year to hay fever?
Some people are such losers that fear is the only thing that gives their pathetic life meaning.
I’m not sure you are 100% right about that, but there is some Darwin sense to it. The viruses that kill their hosts don’t survive either, so the viruses that can just linger around end up surviving.
That said they do mutate quickly, perhaps for that very “reason”. But without intervention with medical advances HIV would probably kill all their hosts. Fortunately it’s not so easy to spread.