Sure.
The baseline is, let's block calls that come from an obviously wrong number. Everybody accepts that. That's done.
The second level is this STIR/SHAKEN stuff. What the big companies don't like is that this is a protocol that you just run on any third party app or on your phone. It will block calls. The calls get tagged as suspicious. Then it's up to you whether you want to block them or not with your software and how you set it.
Phone companies don't necessarily make that much money on that, but it works fairly effectively. There may be problems with how it's implemented transparently and equally. But we'll leave that aside for now. STIR/SHAKEN is what should fix things. It doesn't—they're quite right—catch calls that go outside IP and go through the phone legacy networks. But let's leave that aside, too.
What Bell and Telus are both doing at the network level is...systems that have a sort of different approach. Telus will require a caller to punch in extra numbers in an effort to put a speed bump there. I believe you can get around that if you're a good programmer. It may or may not work. They may or may not be selling that to other providers or to other people who have an involvement with the phone system. They may be selling it directly to customers. The end game, I think, is that they probably want to sell it to customers.
Bell has a different approach, which is network-level blocking which comes with more concerns about how it's being blocked, why it's being blocked, what the system is. That's the secret proceeding going on at the CRTC right now. I think Bell would also like to sell it to consumers at the end. But I don't know. They have the control, as was mentioned, unlike some other carriers because most stuff transits their networks.