The carriers should pick up the ball a little bit and deal with the spam call problem at the network level, rather than leaving it to apps.
How can the tech be broken that call display can be spoofed; like someone obviously from outside of your area spoofs a number in your area. I can't believe that can't be intercepted.
They just don't care beyond collecting a monthly bill from you.
T-Mobile is the front runner carrier for dealing with spam and fraud phone calls in the US. I'll link some official marketing about one of their features, but they are doing a lot in this space. I suspect they find that these features increase brand loyalty per dollar more than the coverage arms race, which they can never win against their deep pocketed opponents.
I've been on Google Fi for a few years, and I don't believe I have received a single spam call, ever. I don't know if that's because Google is just good at filtering, because they operate over T-Mobile's networks, or just a coincidence.
Caller ID originates from the sender and has no authentication. (Bell 303 modem modulation between the 1st and 2nd rings iirc.) I don't believe there is any other data with the call to know the calling number either. (I don't work in Telecom, so take it with a grain of salt as that's just the research I've done as an outsider.)
