He's structurally more conventional.
This is reversion to the mean.
He has shorter pecs and his biceps don't pop. Unfortunately, at the same time, he also inherited a few weaknesses from pops: flat triceps and weak hamstrings. All in all, he looks like a pretty average board-short-class amateur competitor or natural bodybuilder, whereas Arnold had some really exceptional muscle groups that made him stand out and more than compensated for his weaknesses.
No one in natural bodybuilding has really exceptional muscle groups.
