> There's also no evolutionary pressure to conserve its lethality.

That depends on whether the mutations that cause it to replicate better also make it more virulent. The symptoms that help spread Ebola, for example, are the same symptoms that kill those who become infected with it.

The milder it gets, the less it is able to spread because disease symptoms are what help spread the disease in the first place. Also, there are selection pressures that select for increased virulence, otherwise all viruses would have evolved to be completely benign billions of years ago.

the real question is, can we pivot faster than evolution can...