Is it though? Can't you train people on the basics of a single device as a sort of Tier-1 support with the ability to escalate to Tier-2 immediately? Governor Cuomo said in at least one briefing that they were considering training national guard troops to do exactly that.

The device he was referring to was a hand-driven bellows attached to a face mask, and he brought it up as a desperate, last-ditch scenario, ending his description of it with "No, thank you!" Though I think there's a good chance we'll end up there.

Those are a lot simpler and safer than a mechanical ventilator, which requires intubation or a tracheostomy, which you might say is highly invasive of the respiratory abstraction layer, and can cause correspondingly subtle and messy failures.

People who are experts in using one class of ventilators (ICU) are already being trained in using a different class of ventilator (anaesthetics), and they're somewhat concerned about this because of the differences in the machines. https://twitter.com/aroradrn/status/1244134454001635329?s=20

Your idea is to take a bunch of people who are not experts in ventilating, who have minimal experience with ICU vents, and give them a training course on ICU and anaesthetic vents and hope that they remember the difference and can work out the different panels, while exhausted, while in full PPE.

This is happening, but it's scary.

Your wider point - can we reskill a huge amount of the existing workforce to do a different job - is a good point, but that's already happening. Lots of people are doing jobs that they were not trained to do and they're doing those jobs with minimal re-training. This may help some patients, and it may cause harm to others.