Even still, we just can't scale up PCR like that.

How long does it take to build PCR machines? Why can't we build 100,000 of them (or whatever the appropriate number is)?

If it costs tens of billion dollars, so be it. That's far cheaper than shutting the economy for months at time.

This is essentially a war-time effort we are in. I believe government has the authority to mandate that companies with relevant manufacturing capability build and sell these machines in order to combat the virus.

Yea, having lab experience, I think as long as the equipment, reagents, and consumables are all available, lab techniques scale fairly well. You might be running your scientists ragged between installing the new instruments, keeping all the machines running and prepping assays, but it'll get done.

However, sufficient availability of supplies and equipment for this scale of operation is a pretty big if.