Can't remember right now if it's a EU or a Spain thing, but here they made mandatory to use real numbers on the Caller ID, so you can't use fake or hidden numbers for telemarketing. That way, of you're abusing, your line can easily be tracked, blocked or fined.

There has been some waves of spammer calls, more like "fake job offer calls" or things like that, coming from cell phone numbers, and there's still some telemarketing, but it is way way lower than, say, ten years ago. Orders of magnitude .