Either your definition of a great is really loose, or you're not looking at it objectively.
You get prologues on the road that are effectively individual pursuits. Yes, racing in a velodrome on a curved track is a bit different, but it's not a massively different skill. Wiggins is simply a great time triallist who was also a decent climber for a couple of years and was able to convert that into a TdF win on a super well suited parcours to him.
The fact that he was the first British TdF winner along with his success on the track will mean his legacy will live on, but he really isn't a great of the sport
You get prologues on the road that are effectively individual pursuits. Yes, racing in a velodrome on a curved track is a bit different, but it's not a massively different skill. Wiggins is simply a great time triallist who was also a decent climber for a couple of years and was able to convert that into a TdF win on a super well suited parcours to him.
The fact that he was the first British TdF winner along with his success on the track will mean his legacy will live on, but he really isn't a great of the sport