The idea of being able to saturate those defense systems with even slow (relatively speaking) missiles could well be a winner, provided the launch/reload capability exists.--accomplishing the mission objective at less cost.
Recall, the Fairey Swordfish torpedo planes that disabled the Bismarck were so slow the gunners on the Bismarck had trouble hitting them.
I wonder if there is (or has been developed) a stealth cruise missile on the order of the Tomahawk that would slip in and get the job done? If not, that just might be a niche whose time has come, provided the costs could be held down.
But IIRC, the tooling for the Tomahawk was scrapped during the Clinton Administration.