It is the ultimate prize in wrestling to be Heavyweight Champion. There are of course two belts at present and while this can take away from the prestige, it remains the goal of every superstar to hold the gold. The list of those that have held either of the top two belts is a list of legends.
However there is also a list of wrestlers who have never held the top prize in the WWE; Curt Hennig, Roddy Piper, Jerry Lawler, Jake Roberts, Vader, Rick Rude, Scott Hall, Davey Boy Smith, Jimmy Snuka, Ted DiBiase, Ricky Steamboat. Legends once again.
However in today's wrestling world, if you are talented, you will hold the gold. There is simply too many PPVs, Raws and Smackdowns, and house shows for champions to stay in place for long. It might devalue the belt, but the days of year-long reigns are probably over.
What constitutes a champion is debatable nowadays but there seems to be a small band of mid-card-main event wrestlers who will never get their chance.
Backstage politics, poor mic skills, weak commercial value, etc. The reasons are unknown but it seems that these 10 may be destined to never win the World Title.