21: 2003 Ford Explorer Sport Trac
The problem with the Sport Trac was that it was the prior generation Explorer. But Explorer moved on to a new generation the same year. So consumers who wanted the truck bed option were forced to get an outdated model (via Forbes).
The Explorer Sport Trac did have some nice attributes, but it wasn’t enough to keep it on the market. Sales were lackluster and Ford eventually pulled it from the market. Years later, the brand was revisited for a short period but Ford again killed it off.