In pure coffee terms, no they can't compete with pretty much any cafe/bar in Italy. However arguably Starbucks is a lifestyle choice and some Italians (at least the younger ones) will go somewhere that feels stylish and international. They'll get a shock with the coffee, but the youngsters sometimes take a strong view they want to break free from what they see as parochialism (but I love as Italian culture).
I am sure it will succeed with the younger crowd. I know someone in Milan who has been so excited at the arrival of Starbucks. I can't understand it as I prefer the traditional Italian culture concerning coffee. I am curious to go there to see the differences from Starbucks in America.
After seeing the amount of teenagers at the McDonald's near the Genoa train station, and in other places in Italy, I believe you're right. These businesses have succeeded all over the world where parents have not.
Maybe this is a bit off topic, but strangely enough, the only place Starbucks didn't succeed in setting up shop was here in Israel. Their two-year attempt was quite embarrassing for them (and even a bit of source of pride for the local coffee scene here).
For a read on this (with attached podcast), see the link, if anyone's interested : https://tlv1.fm/business/2016/08/15/why-starbucks-failed-in-israel/
My wife's older cousins kept us supplied with very good homemade wine throughout our visits. Now that they have all passed away, their children/grandchildren happily provide us with very bad homemade beer. Times change -- not always for the better -- but times change.