Earlier quoted context omitted.
> Doctors eventually realized invasive ventilation was a death sentence. Do you have a source that ventilation itself worsens outcomes, and isn't just correlated with already poor-performing patients?
The problem was that for a healthy person, ventilation just moves your lung physiologically, but for very sick patients parts of their lungs are like inflamed tissue paper so the forced inflation could cause problems.
If used properly by trained medical professionals, they are better than the alternative — no ventilation at all.