I used to think this but, when looking at the best interior players in the league, his 720 snaps isn't really that compared to elite interior linemen. I honestly thought that one of the reasons that Raji regressed so much was overuse before I actually looked at how other DTs are used and realized that, no, his use was inline with those other guys.
For comparison, this year Clark has averaged 55.4 snaps per game (in the 13 games he's played this year). Aaron Donald has averaged 58 snaps per game, Fletcher Cox 53.6 snaps per game, Akiem Hicks 50.6 snaps per game, Grady Jarrett 49.6 per game, Suh has averaged 56.3 snaps per game, Cameron Heyward 52.9, DeForest Buckner 53.6, and Leonard Williams 55.6.
Clark has also played 95.3% of the pass rushing snaps on the team (he's missed 13 passing downs all season); and, when removing guys who have played fewer than 100 passing downs, Clark is tied with Cameron Heyward as the 13th best interior pass rusher in the NFL this year, getting pressure on 6.8% of his pass rushes. For reference, Aaron Donald gets pressure 11% of the time he rushes and Chris Jones with the Chiefs is second at 9.1%. Aaron Donald is REALLY freaking good.
Anyway, I guess my point is that, while it would be nice to have other good players on the defense to give Clark a break, the fact is that the Packers' defense had exactly ONE great player in Clark (Daniels' run defense fell off a cliff this year, hopefully it's just a blip) and sitting that guy down would be basically terrible for the defense. While it would be nice to give Clark a few more snaps off per game, his usage isn't too terribly high compared to other great players.