Wouldn't make a dent. The volume of stuff they put out is massive. I've actually heard somewhere that many of the Nigerian scams are run by organized crime. It may not seem too profitable, given how few suckers fall for it, but given the average income in the region, all it takes is one big one to fund the operation for years.

Yes - it's mostly organized crime. The more money they get from a victim, the higher up the chain of command the mark is passed until eventually they have bled him or her dry.

Some people have actually travelled to Nigeria to get their money back, only to be kidnapped. The family then has to pay even more money to get them released.

Many newspaper articles claim that the this scam is the second largest industry in Nigeria although none provide a source for this factoid.