i've been looking for that data point. it's hard to find. i interact with a person on twitter who is convinced that all the emphasis on ventilators is misplaced because those people are all gonna die anyways, they just die slower with a ventilator.
20% is a little lower than i'd guess for the global recovery rate for intubated patients, but it does seem like if they put you on a ventilator, that's really bad news.