Both of them are 7'1" and some change without shoes, and north of 300lbs, while also being coordinated.
It seems like there's a 30 year gap between when someone that big surfaces while also being coordinated and much more agile than they should be. There's no doubt in my mind someone with similar physical traits appears, and they will play big because what else will they do? It just boils down to a matter of when, for all we know that person could be in grade school right now
Bynum is actually the closest, he was 7'0 3/4th without shoes at the age of 17, just not as mobile as either of them because of his chronically bad knees. His first knee surgery was in middle school, he may have been the one if it weren't for those crappy knees.