It would be fascinating to know what processes bands go through when deciding to release singles. Rush's 1990 album Presto produced 3 singles: "Show Don't Tell," the opening cut, "The Pass," and "Superconductor." But if I'd had a say in the process, I would have tried to convince them to release "Available Light," the album's final track.
I really think this track could have been a hit. For that matter it's a Rush tune that might actually do someone quite well if they covered it. Unfortunately a hamfisted cover "Tom Sawyer" is much more likely to be in some artist's plans.