The problem with looking at the normal path of viral mutation is that humanity isn't using its normal virus management behavior.

Normally, people who get seriously sick get relatively isolated, so more serious mutations have little opportunity to spread, while people who suffer few if any symptoms continue to live as normal, allowing less serious mutations to spread widely. This is what ended the Ebola outbreak in central Africa a few years ago.

However, if everyone isolates regardless of symptoms, the deadliness of the virus has little to no impact on its ability to spread, so only its infectivity will be affected. We are guiding the virus to remain deadly and become highly infective.

The only worse management of viral evolution was done during World War One, when young men who suffered serious symptoms of the Flu in the trenches would be pulled back from the line, and those who suffered minor symptoms would stay on the line to be thrown to the meat grinder. It actively selected for more infective, more deadly variants, that were able to cause deadly symptoms in young adults.