Just noticed this thread is 24 years old. That's awesome! And we're still finding Worst Bands!
But it should be more like "Forgettable Bands". I mean, all the bands mentioned so far (well, most of them) were quite successful and had/have millions of fans, so there's no calling them "Worst."
But think of bands/artists who came and went quickly who don't still live on their catalog. Rockwell; Ma$e; Magic!; Dido. (actually, no on Dido - she's still worth $15 million based on catalog streams). But you know what I mean.