there are still many people on the streets...
remember that there are 10 million people in a realtively small are, which incidentally is also the core of the economical, industrial and financial system of the whole Country...
this means that we can't stop all the jobs, we just can't close everything down as they apparently did in Wuhan (for instance), otherwise the whole Nation would go bankrupt in a while...
add to this the fact that the early mishandling of the situation led to many doctors and hospital personnel to get infected as well, with the consequence that many people already hospitalized for other issues had been infected this way, causing a lot of deaths because if you are already facing cancer or other bad diseases, this virus almost automatically gives you the final push to the end...
moreover, usually Italian family members have always intense relationships, seeing each other very often also among the non strict relatives...
and our attitude doesn't make ourselves the most disciplined people in the world (many thousends of violations have been recorded only in the last few days, even this is more a problem of the Central/Southern regions rather than Lombardy, where however it's been estimated that 40% of residents every day move for some reason -most of them for good reasons and within authorized parameters, but still)...
put all these aspects together and you have the perfect storm, with basically minimal chance to limit the damage in a very consistent way...