Couple of things .. You're right that football wise he'd be better off at Everton, I think he prefers Anderlecht on a personal level (staying near his home) .. Secondly, he's got nothing in common with Fellaini that would make them seek each others company , culturally speaking you're either Flemish or Walloon - there is no Belgian identity (not that I think that is a problem) .. Finally, I don't see what the difference is between AZ, Ajax and Anderlecht; Ajax might have a better youth program but De Bruyne would play first team football for those clubs and right now Anderlecht are the better team.