Having been surprised to see Tool twice in this thread, I think you hit the nail on the head.

Between Maynard’s voice, and the basslines OP mentioned, they definitely have a distinctive sound, and I could see how it could blur together as background / casual listening music. Especially if you listen to mostly mixes ot playlists.

Personally, I almost exclusively listen to music by album, and I think thats where Tool’s songs really become more distinct from each other.