fizzled. Third-Eye Blind from the 90s is what made me think of this question--though I'm sure there's bigger ones. Their three top ten hits were Semi-Charmed Life, Jumper, and How's It Going to Be. Sure they had people that still followed them and their next album did well--but probably more based on the success of the first one.

Any others that had a really big first album but just went away?

By the way, I owned Third-Eye Blind debut album when it came out and am not just discovering the last three tracks on it are actually really good.