Yeah except Thomas is shooting 48% both from the field and from 3, while Damian is shooting 38% from the field and 23% from 3.
You're just looking at total points LOL.
You're just looking at individual efficiency without factoring in who's around them.
Lets compare:
Crowder > Harkless
-Crowder is a 42% shooter, and can put the ball on the floor. Harkless isn't a great shooter and can't create for himself
Johnson > Aminu
-Johnson shoots 36% from 3 and can score down low, Aminu can't hit shit.
Horford > Plumlee
Horford can shoot from 3pt and mid range, Plumlee can't make a shot outside of 2 feet.
Therefore, Lillard is relied on to do everything, and take every shot. In clutch time, most of these players get open and pass the ball immediately back to Lillard, causing Lillard to have to get a shot off against a defense cheating off of our 3, 4, and 5 man because they can't do anything.
Meanwhile, Thomas can pass the ball and his teammates will actually look to shoot and hit shots. This keeps the defense from cheating off Thomas, allowing him to get easier shots (especially because there's almost always 4 shooters around him while Lillard only has 1 or 2.)
I know you love hating on Lillard, (Hi Tunchi), but be objective and look at the full picture. Remember Lillard when he had Matthews, Batum, and Aldridge around him? He hit a high percentage of shots he took in the clutch (and they weren't even as good as the shooters Thomas has around him).
It's annoying when Lillard will give the ball to Plumlee 5 feet from the rim, he'll kick to an open Aminu, who passes back to Lillard because he can't shoot. What's Lillard supposed to do then? He's gotta force something himself with no spacing and teammates that can't/don't shoot.