Christopher Caldwell writes in the Financial Times:
Much commentary about immigration to Europe is written as if no reasonable person could possibly care who, specifically, a country’s residents are and where, specifically, they come from. In an age of debt this indifference is not reasonable. No matter Italy’s demographic make-up decades from now, it would be quite natural for the “new generation” of multi-ethnic Italians to ask why they should pay for a decadent “old generation” that carried out its fiscal misdeeds before they (or their parents) were even in the country.
Another problem is that Italy is the land of Dante’s The Divine Comedy and the Sistine Chapel. It might be possible to convince an American or an Australian to believe (or to say) that a big arrival of migrants will be a cultural “enrichment”. It is a harder case to make in Italy, even in the 21st century. Immigration may enrich Italy in many ways, but is unlikely to do so culturally. It is just as unlikely to do so fiscally
And, it's less the old stuff (although some of it, like The David and the Pantheon, is as great as advertised). It's the Italians. I don't think I'd want to live there, but Italy is a great place to visit.
As for the notion that the world will be better off when Italy is filled up with Libyans ...