Why aren't there open-air infirmaries for COVID patients?

No.12491695 ViewReplyOriginalReport
It was common knowledge (or so I thought) that the switch to outdoor, or open-air, infirmaries reduced morbidity and mortality during the 1918 pandemic.
Yet the only quasi-outdoor field hospital set up in NYC last spring was in Central Park, and it was for non-COVID patients.
Now I see restaurants everywhere with temporary external enclosures kept warm with gas heaters.
Why couldn't our genius doctors and public health officials throw something similar together for COVID patients last March, instead of clustering them indoors in poorly ventilated ICUs?
Why do people believe doctors are smart, when confronted with examples like this?
>https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4504358/
>The surgeon general of the Massachusetts State Guard, William A. Brooks, had no doubt that open-air methods were effective at the hospital, despite much opposition to the therapy. Many doctors felt that patients would get the same benefits if the windows of a conventional ward were open or the patients were put in a hospital “sun parlor.” Brooks, however, held that patients did not do as well in an ordinary hospital, no matter how well ventilated, as they did outdoors. Patients in indoor sun parlors were not exposed to direct sunlight all day as they were when outdoors. He reported that in one general hospital with 76 cases, 20 patients died within three days and 17 nurses fell ill.38 By contrast, according to one estimate, the regimen adopted at the camp reduced the fatality of hospital cases from 40% to about 13%.12 Brooks wrote that “The efficacy of open air treatment has been absolutely proven, and one has only to try it to discover its value.”