Those who need to dissociate with a number have anonymous sim cards in abundance. Costs around $2-5 a piece when ordered in bulk.
That said, such high-tech operation is just a geeks fantasy about spies. When you cross the line where it becomes reality, you’re either a very big name with a sudden drug/rape history or a subject for waterboarding which is the most effective cryptoanalysis tool invented.
While this is a well-trodden stereotype, and it certainly has merit, not all crimes are Snowden-level crimes against the state. Felonies such as embezzlement, fraud and trafficking are often investigated by exposing the digital trail. Law enforcement most definitely do pull those records with a subpoena. It's often one of the first things done (pull all banking and phone records) and is often a key ingredient in a successful conviction.
Yes, burner sims definitely help evade investigations, but they are harder to get nowadays, depending on jurisdiction. For instance you can't pay cash for a SIM in North America. It has to be a credit card or a bank transfer and that's a form of ID.
Ah that's interesting, I did not know this. Maybe this is why authorities are all up in a tizzy over it. Because it can't be their platform security, which is largely theatre.