I agree there’s a lot the carriers could be accomplishing in flagging “inauthentic” behavior of network participants, the root cause of SS7’s lack of authentication and encryption will remain and the problem will fester. Yes, carriers are definitely on the hook for making things better too.

That said, the decisions in Apple's client side software are atrocious for the considerations of 2019.

Aside: No idea why my post went from #1 on HN to the third page in under 30 minutes, I thought we were having a fruitful discussion here