I just ignore any caller ID I don't recognize. (For that matter, I ignore a lot of them that I do.) If someone is already doing something illegal (running a scam), doing something else illegal (ignoring DNC) is hardly going to stop them. So the DNC thing has been an abysmal failure. It's like if someone drives off the road into a playground and kills a bunch of children, they aren't going to care that one of their taillights is out. The DNC is incredibly minor compared to the scam itself.
I've noticed the scam calls come in waves. I'll have none for several weeks, then a flurry of them. I suppose the scammers dial different regions and exchanges sequentially, and it takes them a while to get back to my number.
Like all scams, there is a chain of plausible deniability. Outbound dialing services rent lines to scammers, and can deny they know they are scammers if it ever comes up. Scammers know how long they can use a particular outbound service before they move on. You just can't stop it, because the scammers are ahead of the game. Running their hustle is all they do, so they're better at it than the people who try to stop them.