I'm not surprised if you're right about that, but I would love to see some authoritative sources about specifically which DIY projects would be most effective.

I read some of your links from above, and I agree it's good to be skeptical. I'm basically waiting for hospitals to start announcing that DIY ventilators are the right move, but by the time that happens, it may be too late to start sourcing materials and get things built in time to make a difference.