Let do a bit of math:
Say you send 10,000,00 spam emails and only 5% click on it, that’s 500,000 let’s say out of that only 1% buy. That’s 5000, if say the price is $30US that is $150,000US. As you can see this is extremely profitable. This is why SPAM works. I tell everyone if you want to stop SPAM tell everyone you know to NEVER EVER click on an SPAM AD.
Next the big Telco companies and ISPs do NOT want to stop SPAM they make too much money off SPAM that stopping it would nearly bankrupt them. Think about it. (Hypothetically I am a major SPAMer) and I setup stealth SPAM servers (big servers that can send out 10,000,000 SPAM fast and efficiently) I buy 2 DS3 or 2 OC3 lines from my local Telco for my servers to send out the SPAM. The Telco is making a lot of money off of me. They don’t want to stop me they want to help me do anything they can to keep the money coming. I have seen this over and over the Telco will not shut them down and do a lot to protect the SPAMer because that is their way of making money.