I think having enough cruise missiles on hand to saturate a modern IADS is more expensive than you think. Regardless, even with LO aircraft, the future will still include cruise missiles. It's not really an either or thing; same deal for tailless UAVs. They'll come on line and get integrated into a bigger pie.
AN/TPY-2,
Touche, my brain automatically saw and typed apy vs tpy into google. The THAAD radar may be a really long range X band radar but that doesn't mean nothing gets in either.