Well, the band wasn't named after him

There are a lot of rumours circulating about David Lee Roth’s sudden departure, but one thing’s for sure, it was personal. He and guitarist Eddie Van Halen were at each other’s throats—they completely disagreed over where to take the band musically, Van Halen couldn’t stand Roth’s flamboyant stage presence, and Roth felt like the other members weren’t taking themselves seriously. So he left in 1985 and embarked on a successful solo career, but eventually came back, rejoining the band in 2007.