This is already happening in Europe (and starting to happen here): because the virus spreads primarily through close contact, healthcare workers are at enormous risk, even more so if they lack adequate protective gear, as is increasingly true in the United States. And without healtchare workers, having enough ventilators won't matter.
ADDENDUM: Here are the current CDC recommendations for dealing with the shortage of protective equipment and gear. (Thanks to David Ozonoff for the pointer.)
