You need to google FTC sites and read about those prosecuted because of the dnc.  Quite a few there.  
They do in fact prosecute but first they have to have  to document enough complaints to establish patterns,  pursue,  and then prosecute when enough evidence to convict has been aquired.
In 2012,  the woman who headed up one of the "megan"  credit card services sites was prosecuted.  She got 17.5 years in prison,   her husband got  10 years for abeting,  and several workers got 2 years each.   The past couple months (as reported on this board) has had one of the "Rachel"  credit card scammers busted in Florida,  also
International cooperation arrested some of the scammers in India.    Not perfect but it does help.