We shelled and bombed Iwo Jima for three days, and still the Japanese came out of the tunnels and caves and put up fierce resistance.
No doubt the Houthis are very well dug in (look at Hamas), and we're going to play whack-a-mole for a while. The trick is to destroy every hole they pop out of, and eventually , they will run out of holes. There are only so many sites adequate (because of terrain, geography, etc.), to harbor launch sites, and the geography that is suitable for target acquisition equipment should be limited, too. Concentrate surveillance on those and take them out as they are found.