Why is Joe Mixon under appreciated?

[Forever Spinning Vinyl]

(12-11-2023, 10:35 PM)TheLeonardLeap Wrote: Emmitt Smith averaged 4.4 through his age 27 season, which is where Mixon is currently at in his career.

Emmitt Smith was .5 higher than the league average of that time of 3.9. 
Mixon's 4.1 is .2 LOWER than the league average of 4.3 of that time.

How was Emmitt Smith's o-line during that time? I remember that they were considered the best o-line in the league for those Super Bowl years.