Law--whether prosecution or defense--is a competitive business: it's about who wins and who loses. Selwyn Raab, in "The Five Families," concluded that, after Rudy Giuliani successfully prosecuted the Commission case, US Attorneys around the country fell over themselves prosecuting Mafiosi under RICO so they could have their share of the glory. The FBI was right there with them, seeking glory. But, after 9/11, a lot of those resources were refocused on terrorists, which allowed the Mob to regroup.