Very very few hospitals have actually been overrun. Many were and still are empty (or flooding in with people who couldn't get treatment for other things during the lockdowns). The cases in NYC, Michigan and Kirkland (Seattle) were all due to orders that packed elderly care facilities with sick. Governors Whitmer and Cuomo made huge mistakes with their orders and neither is owing up to it.
The problem is that with the infection spreading exponentially you might have hospitals half empty one day and at 200% a week later.
Here in Czech Republic it looks like we managed to avoid running out of capacity during the ongoing second wave, but just. The measures taken included canceling any elective and non-life-threatening surgeries, drafting medical school students, many foreign doctors that came to help and moving covid patients in critical state from overloaded hospitals hospitals.
We even built two full field hospitals which we will thankfully not need as it looks like. BTW, building one of them took about a week - which you migh not have, once you hit exponential growth. Not to mention having spare medical personnel to run it.
