First off there are a bare handful of CFL teams, so only a few spots for a QB to take up residence.
Second, with 12-man defense and the changes that does to coverages, the CFL tends to rotate between a handful of proven quarterbacks and then just pass them around back and forth. They tend to be very exclusive about which QBs they give a chance to.
I see this all the time and it's pure nonsense, people talk about a draft pick and say that either he'll be an NFL quarterback or he'll go up to the CFL and do really well. And that QB almost invariably does nothing in the CFL because there aren't many rooms at the motel to begin with, the overwhelming majority of them are full, and the motel owner doesn't want to rent to "your kind" (rookies from American colleges).
When Chris Streveler started Week 1 for a CFL team as a rookie from American college, it was the first time that had happened in what, 30 years? I believe only three guys have done it, those being Anthony Calvillo, Joe Theisman, and Chris Streveler. I'm sure you've heard of the other two.
You're sitting here saying he didn't do so well because when Matt Nichols got healthy he got his starting job back, but Matt Nichols is one of those handful of CFL quarterbacks that gets passed around because he's proven. And he performs pretty well. There was never even a possibility for Streveler to earn the job above him, regardless of how well he did.
Streveler started the first three games of the year, as I said becoming only the third rookie to ever do that along with Joe Theisman and Anthony Calvillo, and he went 54 of 86 for 570 yards, 6 TD and 2 INT, with 22 runs for 183 yards and 2 rush TD.
He finished the year 86 of 140 for 1,134 yards, 11 TD and 5 INT, with 77 runs for 441 yards and 10 rush TD.
Chris Streveler isn't in the NFL for one big reason. He doesn't have the arm strength they like.
I tend to be more forgiving of the velocity thing than the NFL. I thought a guy like Streveler, with one of the quickest releases I've ever seen, could make up for the lack of velocity with that fast release and his mobility. The NFL doesn't agree.