Because Italy is moving towards both peak contagion and therefore peak deaths, which will come after peak contagion.
I spent a long time this morning (getting fed up of the "but Italians all live in mixed generation households" trope...and guess what- 1.2 % of Italian households at the last census were multi generational. In the UK The Guardian says 1.9 million households are multi-generational. So, slight population variable aside, it's more or less the same number.
I imagine the components will be different though. The Italian families are probably nuclear families who move Gran in when Grandad dies, or less well off families who live in better off Gran's house with her. I imagine that in the UK it's more likely to be single parents with children living with their parents, given the lack of opportunity for them to do otherwise and the high teen pregnancy rate (though I think that is coming down from figures about 15 years ago)