Admittedly, some may not even consider the animated films, and relatively few of the Japanese-produced live-action films get much notice outside of Japan.
Still, there's been a growing wave of American (or international) live-action films based on manga properties. From THE GUYVER, to DEATH NOTE, to GHOST IN THE SHELL, to the quite recent BATTLE ANGEL ALITA, and I would have thought those wouldn't have escaped people's notice. A live-action AKIRA is now in production, as well. The Spielberg-directed (based on an unfinished Stanley Kubrick production) film A.I. is virtually a live-action adaptation (uncredited) of Astro Boy, too.
There have been plenty of Japanese-made live-action, box-office bombs too, from DEVILMAN, to CAPTAIN HARLOCK, to GATCHAMAN. I kind of liked TETSUJIN 28 and CUTEY HONEY (at least the first half of it), though.