The problem with this reasoning is that your measure is not a direct measure of infection rates. For South Korea, they tested a large number initially, and now fewer. We don’t know if it’s actually under control without more systematic testing and therefore data on infection rates.

The other issue is that of getting the leak at the wrong time. If the UK manages to partly control it, but then realises containment will fail in say November, the peak will occur at the worst possible time in winter.

By controlling the spread and aiming for summer, best medical care can be achieved given limited resources.

This logic is not true for equatorial countries such as Singapore due a lessened seasonal effect, so they should continue with their current Methodology. I suspect others will move to the UK approach once initial social distancing process inadequate (assuming they are that is).