I didn't see anything in there about penalties for carriers not enforcing this. Also willing to bet they beg for extensions claiming they're not ready - or too costly to implement.
All the major carriers are implementing a STIR/SHAKEN strategy that should be in effect by next year. But it is complicated to do and there may still be problems when they do - as others have explained here it's not as simple as it first appears.
I don't have any sympathy for the operators in this. They've profited from this for long enough and ignored the problem. There's a lot of pressure on them to solve it and the impression I have is that there's no appetite for "the dog ate my homework" excuses from regulators so let's see.
The spoofed caller ID to match your local area code has landed on people in my contact list, and it was extremely jarring to think "why is my best friend's mom calling me out of the blue" and get offered a discount cruise by a robot.