It is easy for the spammers to hide, but its quite easy to find their customers.  They are selling something, and its alot easier to track the money.  Of course it depends on what country they are in as to whether something can be done about them (legally that is).
 
John G
usgravitics.com
"Better Living With Gravity"
>>Run-of-the mill spammers and mail bombers now frequently cover their tracks via "anonymous mailers" and "spoofing," Thackeray says. By "looping" their email around the world and rerouting replies to dummy sites to disguise the origin of incoming mail-- and rerouting replies to dummy sites-- digital criminals are outmaneuvering law enforcement altogether.