Carriers can certainly carry an amount of blame. IIRC in Aus its gotten harder to activate a new sim for these reasons. The attacks haven't stopped entirely but

Carriers can certainly carry an amount of blame. IIRC in Aus its gotten harder to activate a new sim for these reasons. The attacks haven't stopped entirely but its gotten more rare. It now relies on a very persistent social engineering attack to pull off. That said number portability is a really deep well. And theres utility in keeping it somewhat liquid for the many many many people it benefits rather than making it terrible for everyone to prevent a number of attacks.