88% of the deaths in Italy have been aged 70+, 96% have been aged 60+. Presumably the vast majority of the 4% younger had chronic conditions.
It seems to me much more sensible, and certainly much less damaging to the quality of life of the majority of the population, to focus on isolating those susceptible groups to a level where their infection rates are within what the NHS can handle. With the advantage that the younger population will be exposed to the virus, develop resistance, and then be in a better position to assist those who succumb more seriously.