The results show that inequality of opportunities, real or perceived, drive the electorate and that the centre-left, in Italy possibly even more than elsewhere, is seen as the party of the spoiled establishment. In Milano, Turin or Bologna, the upper middle-class in city centres voted for the centre-left, while the lower middle-class in Southern Italy was fully behind the 5 Stars Movement. This is the crux of the matter, much more than the nature of the political regime.
"and that the centre-left, in Italy possibly even more than elsewhere, is seen as the party of the spoiled establishment"
As an American, I won't claim any real, in-depth knowledge of Italian politics. However, in the U.S., the center-left is the party of the spoiled establishment. Just look at who supported Hillary, and who threw a temper tantrum when she lost (other than her, that it). The upscale liberal establishment loved her. Of course, she got the racial identity politics vote. The rest of the American people were disgusted by her and voted from Trump.