In your example, a 30% mortality rate is a very big deal. If we had a hypothetical cure that killed 30% of the people it was administered to, I doubt it would get very far.

I'm not saying the alternative is do nothing. But playing doctor because you think that you're reasonably qualified to administer a ventilator, then we're going to end up with, say 30% mortality rates from patients whose lungs were sucked through a ventilator tube because you guessed the wrong pressure. Or, more realistically, a terrible infection because you decided soap and water in the bathroom sink would be sufficient to clean the apparatus.

And then what do you suppose will happen after 30% of these amateur medical procedures go South? Are you going to throw in the towel, try something even more reckless, or decide that you need to get an actual doctor involved to clean up your mess? At which point, you've just added yet another case to the already overburdened medical system. And at a 30% failure rate, that would become a major burden.

There's a lot of room for action between doing nothing and acting foolishly (such as claiming a 30% mortality rate for botched medical procedures is a rational tradeoff). There are ways to help the situation here that don't involve magically becoming a nurse overnight.

The thing you’re missing is these new RTs wold not just be treating COVID-19 patients. There are tons of people who will need ventilator therapy because they were injured or sick and they would have gotten injured or sick anyway. These are people who can be saved with proper treatment or injured by improper treatment. Barotrauma and lack of tidal volume have implications beyond simply alive or dead. We need people but we must make sure they can actually provide adequate treatment.