Regarding taxes, it's pretty ridiculous, I would never encourage people to open a business here if they can avoid it.
I'm moving to the US next year and I can't wait to stop paying the ridiculous amount of money (in proportion of what I earn) that I pay now as a consultant.
I think I can add another reason why doing startups is hard in Italy: finding a cofounder or team members. I've worked in one of the biggest startup incubator in Italy (h-farm), and I can say from experience that it's super hard to find talented people, and that makes a difference at the end of the day.