A product of his offense. If you add in Dak's rushing TD's, his yardage & TD totals his first 3 years are very similar to what Romo did in 2014 when the Cowboys started using a more balanced run/pass attack. Besides, the job of the QB is to do what the team needs, not simply put up big stats for the sake of putting up big stats. Aikman was never a big stats guy, but he was what those 1990's teams needed at QB.
But I see the slant here - in the years the yardage & TD totals are more modest, wins mean nothing and stats are the key, and when he puts up the stats suddenly it's the wins that matter and stats mean nothing.