Survival of the fittest.
Simple fact of the matter is that nothing we do to limit the spammers will stop them. At least on the technical side of things anyway. The only way to defeat spammers and malware authors is to require that all internet users are educated in the basics of IT security before they are allowed to go online.
A lot of the people who read the Reg are very talented IT experts but most peeps out in the real world know nothing about how computers work or filtering systems etc. They want point and click computing. Like they get with the TV turn it on and what you want happens. These people are the weak link, the dumb users the targets.
Remove the dumb user from the equation and the spammer has no target. Educating users in basic safety and security is the only way to do this. Anyone without this basic common sense knowledge should not be allowed to have an internet connection, until they have been taught it.
This would not mean going back to school or anything like it. Just some simple guidance from the ISP's when they install the service for the user. Back that up with a decent user support line to provide both technical help and basic tutoring in IT security to our less technical members of the community and there you have it.
Show people how to defend themselves before they come under attack rather than expecting them to know how to do it or where to look for the info themselves.
Simple idea really but until it is made an industry wide standard then we will always have the poor dumb user and the spammer.