the US would have fewer cases if it locked up an entire theme park full of customers and refused to let them out until they were tested after tying in a single positive case (and she merely rode the subway in the area, she wasn't actually at
Disneyland)
The countries that have decided to fully eradicate the virus (and they're having a hard time with the Delta variant) do tend to have lower numbers because they lock down at any positivity in the area. Other countries have gone the vaccination route - lots of cases, but fewer deaths and hospitalizations recorded than before widespread vaccination. UK coronavirus stats today were 39,682 new cases and 40 deaths.