It's different now - because of the strict quarantine requests, coupled with the knowledge that there's no known treatment/vaccine, coupled with the fact that y

It's different now - because of the strict quarantine requests, coupled with the knowledge that there's no known treatment/vaccine, coupled with the fact that you have literally tens of thousands of cases per day - means that people don't cooperate that much, and the system is already over-stretched. Also, "hasn't worked at scale anywhere is false" - AFAIK it worked fairly well in South Korea, Japan, New Zeeland, China.