Re: Why is this so prevalent
"Someone in Kosovo is making many calls all over Europe everyday and this goes unnoticed."
Presumably there are "legitimate" call centres making marketing spam calls and possibly really legitimate call-centres making bona fide outbound calls. Without a legal requirement to do so it wouldn't be the Telcos role to police this nor would they have the incentive to do so voluntarily.
I've previously suggested a means to incentivise them. Enable the subscribers to report a recently received call by dialling a specific code. The originating number, as opposed to the faked number would be traced. If that were a subscriber of the same telco the caller would be charged a fee on the recipient's behalf to be credited to the recipient's account plus the telco's handling charge. The fee would naturally be higher for a recipient on a scheme such as TPS. If the call originated outside of the final telco's control the charges would be passed back to the telco who had forwarded it. They could then pass it on with their own handling charge until it arrived as a charge on either the caller's account or with a telco which had been insufficiently concerned to keep logs. Naturally some statistical work would be involved to set a minimum number of reports from different recipients to prevent someone trying to make money out of legitimate calls.
On one level it would be to reimburse recipients of junk calls but would also help trace fraudulent calls. On another it would kill the whole call centre scam by making it unprofitable if the charges were paid which in turn would ensure telcos' credit control would make it much harder to set up anything other than bona fide call centres.
On another level it would involve telcos making investments needed to implement it with the knowledge that by stopping the calls they'd never get their investment back in handling charges.
On the real level bringing such a scheme forward as a serious proposal would very likely lead to telcos, ever anxious to help the authorities discovering some much simpler, cheaper and hitherto overlooked means to block what they adgreed was this disgraceful abuse of telecommunication systems.