MANTHA IS/WAS ON ONE OF THE WORST TEAM IN RECORDED NHL HISTORY.
The Red Wings had like four NHL caliber players on their roster last year. Mantha was one of them. Their defense had Filip Hronek (who is dogshit defensively still) and a bunch of either completely washed up has-beens or a group of never-will-bes. Like don't remotely try to compare DeBrusk and Mantha and paint them as anything close to equal. DeBrusk is on a loaded team. Those 2nd line minutes? He's not facing the guys that Marchand, Bergeron, and Pastrnak were. The Bertuzzi, Larkin, Mantha line last year was quite literally Detroit's only hope for points. I mean, look at the +/- of the guys on Detroit's second line. Andreas Athanasiou -45, Filppula -42, that means those f***ers weren't scoring.
Also... DeBrusk played 1043 minutes last year and had 35 points. Mantha played 812 and had 38. What the hell are you talking about?
Extend that further... Debrusk had 167 power play minutes. Mantha had 141. So, Debrusk played more minutes with more minutes on the power play against worse quality of competition... and still didn't have as many points. But yeah, they're about equal.