Sanders: FTP tops 5.5-5.6 w/kg, Chris Froome and fellow aliens: FTP 6.5 w/kg. That’s 14-16% less.
I would think that long course athletes won’t have peak w/kg numbers for triathletes because they tend to weigh a bit more than short coursers. But even in absolute power someone like Sanders is giving up 60-70 watts to someone like Cancellara in FTP, similar discrepancy as w/kg.