I do not understand why people keep saying AD can't catch up with HS missiles. Doesn't AD systems calculate speed and trajectory before counter missiles are launched ?
Unless you need to catch up to a missile from behind all AD needs to do is intercept.
It can intercept but reaction time matters; it is dramatically reduced (1/4th or less), the anti-ship BM missile attacks from an higher altitude, easier to detect and track compared to sea-skimming cruise missiles but harder to intercept because they accelerate to hyper sonic speeds in the range-altitude which can be intercepted by CIWS or point defense missiles.
This is why sea-skimming HS cruise missiles are a game changer but, it is complicated in terms of gaining speed, loosing maneuverability; maneuverability can matter at the most inner layer where CIWS engage with bullets.
Detected at 40km, a ship with has 7-8+ interception attempt at subsonic cruise missile (total of 200 seconds), 3-4 (at most) attempt at HS cruise missile(total of 40-50 seconds, engagement is 20-30 seconds remained after preps).
Anti-Ship BM detected at 200+ (depends on radar config), gives 200 seconds (with Smart-S eqv.) to prepare, 10-20 seconds to engage. Because it approaches from above, even engaged with CIWS the remains may damage the ship.
But it also complicates the equation, the ships ,expecting a known threat, lays an eye on horizon more than they look at high up for self-protection even though it is automatized nowadays it will take time until enemy has adapted to it.
Re-configuration of flight paths with self -decision maker cruise missiles is important too, that is why KEMENT is as much important as anti-ship BM.