> Thing is, pretty much all of this missile defence technology is about to become obsolete once hypersonic missiles become more widespread, which is going to happen pretty soon.

I think you'll have to be more specific.

Or I guess to compare with your other observation: """Even with all this protection, Iran [sent] enough ballistic missiles to overwhelm the defences""" -- It's not a binary of "have missile defense or not => every missile will be shot down". An amount of missile defense will make it harder for missiles to successfully hit a target.

Similarly with hypersonic missiles, it's not the binary of "I have a missile that's difficult to defend against, I win".

Having a sword which can defeat a shield isn't in itself sufficient to obsolete the shield. (Infantry can be killed with bullets, yet infantry remain an important part of fighting despite that).