It has to be successful at some level, otherwise why would they keep sending it?
So I don't think it will ever be solved because fundamentally it's a human issue, not a technological one. While people remain gullible the spammers will be there to take advantage.
Not while incentives for spamming others still exist. If corporations and governments are still seeing the internet as a way to maximize profits/popular approval, the spam will always be the norm.