South Korea, Singapore and Taiwan have shown that you can manage this with high testing, tracking and isolation, but Italy could not?
The thing is by testing and tracking, you go test asymptomatic people who have been in contact with symptomatic people and isolate them. There are in fact examples of this...
Wuhan was Wuhan because China ignored the problem until it needed shut downs. Italy the same, and US the same. But there were countries that didn't do that.