There's a few factors at play here. 1) Hospitals generally get paid (by someone) for treating patients. So they want to run at 100% capacity, even with covid p

There's a few factors at play here. 1) Hospitals generally get paid (by someone) for treating patients. So they want to run at 100% capacity, even with covid patients. 2) You can't really just "build an ICU." You can stand up a field hospital that's able to provide similar, degraded services. But it's not going to be the same. Imagine if someone said "set up a datacenter in a field," and then a customer had a choice to colo their server in a purpose-built DC or your field DC. Which do you think they'd pick? 3) The units that staffed these facilities were heavily augmented by military reserves. Corpsmen may have non-medical civilian jobs, but what do you think military reserve critical care nurses and doctors do for a living? If these field hospitals were packed to the brim, all of those people would be locked in place. Possibly while they were needed in their civilian positions, in their home cities (although the military seems to have done a pretty good job about preferentially pulling non-Covid-civilian personnel). 4) Exponential growth with unknown but high R_t. +1 week before we locked down would have looked very different. ... all of that to essentially say that these facilities were designed as surge capacity, in the event they were needed. We intentionally filled up hospitals first. USD$660M seems like a reasonable price to pay, strictly as insurance, given the very real risk that hospitals would have been overfilled and covid-related mortality would have spiked due to lack of care.