You would think so. However, the number of scam/spam calls I receive daily proves otherwise. When I look up these numbers, they are mostly CLEC or mobile numbers. I assume some of the caller IDs are still spoofed, though I thought STIR/SHAKEN was going to fix that.
The reported names can be entirely spoofed, but the telecom engineers know who they are connected to, and the companies they are connected to know who they are connected to ad infinum.
Without big fines, don't companies make more money not following up on it?
1) VOIP providers get revenue from the customer (scammer.)
2) Upstream telcos are getting paid by the VOIP provider for the numbers, call origination fees, etc.
3) The receiving telcos get some call termination fees.
No one outside the telecom's accounting department will have the figures handy to know either way. And the net balance would certainly would be proprietary information that won't be shared on HN in any case.
Approximately 50% of the calls I receive are through a company identified as "Sinch". Some complaints about them here: https://scammer.info/t/sinch-and-inteliquent/85531
Sadly, scams are big business.