Explain PSG then?
Or Anzhi or any of the Russian or Ukranian teams?
YOur question has been answered numerous times in the last to pages, but lets sum it up since you insist:
1) ATM investing in Italy isn't exactly something interesting, it's very risky, the country is in a mess....you have to give it a lot of thought. Hell even the scandals the league has gone through are enough to scare off possible foreigner investors. If you're gonna invest in Italy, it's gotta be something that you know will get you profits.
2) Yes Serie A has a bigger brand name than League 1 or Russian or Ukrainian leagues, thing here is, Milan is bigger brand name than PSG, Anzhi, etc. And what Berlu wants its more than what any of those clubs cost. So this means, Milan costs more than those teams in a league that's dropping its value. It's much less risky to invest in a PSG in a league 1 since it's less money to invest than in Milan in Serie A. Smart, rational investors avoid big risks that have more chances of implying losses than profits at all costs.
3) Russian, Ukrainian teams and Roma all cost much less than Milan, and were bought by investors of their own country or in Roma's case are descendents from italians. A foreign investor is even harder to attract.
4) If Serie A atm was in a top situation like it was in the 90's or early in the millenium, then yes, it's MUCH less risky to invest big money in a team that is in a strong league (either that or if Milan was in a situation a la Madrid-Barcelona).
5) Galliani pretty much said "hey we got the doors open, just no one has been interested in investing". That alone should tell you something. I know Galliani wouldn't openly say we got tons of people wanting to invest, nor will he name them, but he wouldn't have said so directly that we have attracted no one.
So hope now you can gather why is PSG, Anzhi, etc different from Milan's case.