Those can only be used a short time per person and do not offer automatic unattended usage. You literally have to have at least a 1:1 staff:patient ratio to use them, and that only for a short time.
I am sure that it would be fairly easy to get some air, gas or electric piston parts that simply presses that compression bag on a fixed cycle. You wouldn’t need 1:1 personnel but you would need someone keeping an eye to make sure they were functioning continually.
With millions newly unemployed this should not be a problem.
I can train a housekeeper to sit and squeeze the bag every 5 seconds
I was looking up on if it was possible to build a homemade mechanical ventilator. You can - but it is beyond me.
But I did come across some family in China (a few years ago) that had been using a hand operated one like this for something like 2 months(?) or was it years to keep their young son alive! Everybody in the family taking turns.
The article was about how somebody finally donated them a real ventilator.
Or a patient with sufficient strength and awareness to squeeze his own. While awake, of course.