Well something must be working because I have only had one cold call in the last ten years. We never got very many but now it's so rare as to be worth remarking on if it happens. That one cold call turned out to have been a mistake on the part of an otherwise well behaved company who were very apologetic when I pointed out that my number was on the register.
Companies do occasionally get fined.
I have had a couple of calls from outside the country but I generally just don't answer unrecognized numbers from outside the countries that I have a connection with.
I don't know about Norway, but the UK Telephone Preference Service does issue a number of fines for the line marketing calls they are responsible for, with enforcement via the Information Commissioner's Office (ICO, the GDPR people too): https://www.tpsonline.org.uk/pages/enforcement
Obviously if scammers are willing to commit serious fraud that will definitely result in prison if caught, they're probably not too worried about that. Along with scams, silent calls also fall under Ofcom's jurisdiction: https://www.ofcom.org.uk/complaints/complain-about-phones-or...
The problem is that it's nearly impossible to enforce this. Would be curious to know if Norway has had any better luck.