I do not have that much to add to Luca T.'s analysis, so I'll just limit myself to adding a couple of comments, and to reiterating some opinions and facts that I already stated in some related posts.
First, let me go on record once more as stating clearly that there is a lot of talent in Italian universities. Italian researchers perform very well despite the lack of support the system gives them. However, Italy must do its very best to attract outstanding, foreign scientists (and students) in order to compensate for its brain drain. (I hate this expression, but it has become so widely used that I am forced to use it too.) This won't happen unless much needed, expensive, and probably very unpopular structural changes are made.
Every CS department in virtually every university that matters in the world has foreign members of staff and foreign students (at least at MSc and PhD level). A look at an average Italian department paints a different picture. According to the interesting little book Ipotesi sull'università by the mathematicians Mariano Giaquinta and Angelo Guerraggio only 2% of the students in Italian universities are foreigners. Moreover, for good or for worse, an observer is not unlikely to notice a certain amount of academic inbreeding in the lineage of members of staff.
Something is badly wrong when a school of the outstanding quality of the Scuola Normale Superiore di Pisa has 11 PhD scholarships in mathematics, receives only 13 applications (all from Italian candidates, and none from the school itself), and selects only 4. (Source: Una storia inquietante (An unresting story) by Mariano Giaquinta and Angelo Guerraggio in Lettera Matematica Pristem 60, pp. 4-6.) Does this mean that even a school of that quality does not advertise its vacancies internationally? Or, possibly even worse, does this mean that no student out there perceives that school in Italy as a good location for PhD education? The lack of local applicants might be read as indicating that Italian students with an MSc in mathematics from the Scuola Normale Superiore di Pisa prefer to work on their PhDs somewhere else, and most likely abroad. This is great, but history shows that not many of those people will make the trip back to Italy to bring back to my home country the experience they have amassed abroad.
One of the online comments to the Nature news item reads:
Usually Italian scientists working in Italy are the best one.Italy is indeed a lovely place to live. However, data like the aforementioned ones seems to indicate that it is not quite correct to say an Italian scientist won't go abroad if (s)he can remain in Italy. A look at at the list of people I compiled off the top of my head while writing this post indicates otherwise. The writer of that comment might ask himself why foreign researchers do not consider Italy as an attractive working place despite being a lovely place to live. The answer won't be pretty.
In fact, an Italian scientist will not go abroad for a Ph.D. or postdoc
if she/he can remain in Italy with a good salary.
This is due to the fact that Italy is a wonderful place to live. So, it is true that in Italy there are very few research positions
but they are usually occupied by the best ones.
As an Italian abroad, I sincerely hope that things will change soon.