If amateur ventilators are only used when ventilation is required and standard ventilators are not available, that still may be a good answer.. still, I am sure that there are better and worse designs for amateur ventilators, it would be best if someone who knew they were doing reviewed various designs and could recommend the best of the bad situations.
More amateur intuition: there are probably more available trained health care providers (e.g. radiologists who put tubes in as med students) than there are devices. These things aren't going to be needed by "us", but by them. They need to be the ones coming up to speed.
Again: I'd be sort of OK with a ventilator manufactured by a HN reader. Under no circumstances do I want a software geek putting a tube in me.
I read this as "how to save a life with a vaccuum cleaner in extremis", and not "here's a good ventilator design". Is it a good idea? I dunno. I'll check on the vaccuum today just in case.
Also FWIW: the air path doesn't seem like the critical piece here. My (amateur) intuition tells me that the number of lives saved by amateur ventilators will be rather less than the number killed by amateur intubation devices.