I'm not sure I understand your breakdown of solo artists, it doesn't follow @chayro 's original post.
Are you saying Debbie Harry was better solo than when she fronted Blondie? And Clapton, you don't mention Cream. Was his solo career better?
Rockpile is a complicated one. Dave Edmonds is a great talent and is intertwined with Nick Lowe and Rockpile. IMO, solo Edmonds would be greater than the one-off Rockpile. I was lucky enough to see Rockpile live as headliners circa 1980.