iron dome is about $100k to intercept according to wikipedia. Millions is off by an order of magnatude. I suspect they can make it cheaper with scale as well.

$100k is the cost of the low-speed ~mach 2.2 Tamir interceptor, which is effective against shells and rockets but not going to intercept a maneuvering mach 7 glide body.

There is absolutely no way anyone is producing a manoeuvring mach 7 missile for $100,000 though.

The term "hypersonic" is incredibly overloaded.