Makes a lot of sense, actually. After what, 25 years? guys can start to rub each other the wrong way a bit (or get musically apathetic or redundant) and sometimes a split is necesary to keep things from escalating. That doesn't preclude a future "reunion" or the like, but some times you just need to move on. Heck, I've played with a bass player a couple of times whose desire to be part of a group goes strong for about 8 months and then wanes quickly. A quarter century (ish) is pretty good.