You need to go do some reading. The DNC is just a list of numbers maintained by the FTC. No Army of enforcers, no one monitoring anyone's calls, no mechanical call blocking devices and It doesn't enforce anything and wasn't created to. Just a list that you put your name on asking not to be called. Whether you are called or not depends upon the honesty of the callers. It is an impossible task both economically and physically to run down and try to prosecute each and every complaint filed with them.
The caller doesn't really need your number. Most scam calls are "robo" calls meaning a machine just starts dialing numbers changing a digit at a time automatically. They are illegal to cell phones but of course these people don't care. Also the number that shows up on your ID can be "spoofed", that is the robo system is set up to show a number that is chosen by the machine. Doesn't even have to an active number or even a real number. This is the reason authorities have a real problem in determining who is really making the calls.
JoeNJ, I don't doubt anything you've said. I don't understand, though, that my government can track every financial transaction I make--no matter how small--but they can't figure out who's paying the bills for these scam calls. When I rule the world spam/scam calls are going to be felonies.