Another interesting point they bring up is the propensity of viruses to evolve over time to become LESS lethal.
It is in a virus's best interests to not kill its host, or least to not kill its host too quickly. It will, by logic, evolve over time to become less lethal.
Think of the common cold. That virus, when it first jumped to humans, (assuming we had perfect historical knowledge, which we don't) was probably much more lethal to humans in the beginning. But over time it evolved to 'figure out' the fact that it could survive and propagate more if it became less lethal. Take the evolution of it and extrapolate it and we now have a relatively benign virus that makes us cough (thus effectively spreading the virus) but otherwise does little to no real damage to us. You could argue that the common cold is a very highly specialized and evolved species of virus. It has 'learned' to live alongside humans, how to use humans to propagate its own genome, but at the same time does not kill those humans.
In other words, the common cold is a very highly evolved and successful critter. It has, through evolutionary time, found that sweet spot where it knows how to make humans cough, but it also knows how to not kill the humans that it infects. Thus, it survives and thrives through time, which is exactly what every critter on Earth is always attempting to do at all times.
COVID has a lot of work to do in order to get to this point, and the cycles it needs to go through to get there might well last longer than any of our lifetimes, but the good news is that most viruses actually DON'T want to kill their hosts. Most viruses are trying to find that perfect balance that the common cold has already found. Namely, "Do something to the host that makes them spread us around, but don't kill any of them in the process."