Schenn plays with Holloway and Kyrou, two of the top forwards on St. Louis, who have 47 and 42 points respectively. Playing with them, Schenn has 34 points, averaging 17:34 per game. He isn't getting much PP time here, though that is really only 5 of his points.
I'm all for trying to get a younger guy, someone like Krebs. Now Krebs actually is more productive/60 than Schenn is. That is mostly playing with guys who have 5 and 9 points on the year...
A guy like Krebs has a lower cap hit, is younger, has years of control, and would cost less to trade for.
And most importantly, is already more productive.