Arguably the worst QBs in the league right now are Mitchell, MBT and Collaros...
I'd say the era of big QB contracts might be over - teams with the best OL are winning.
One of the problems with the CFL is its ability to find and develop capable QBs, let alone exciting ones. So many teams opt for the "game managers" to just give em a chance to win every week, instead of rolling with the growing pains of some of these younger QBs - and on the flip side, if you aren't getting those reps (other than 3rd and short sneaks) to become a starting QB, there's only so many seasons you can tolerate of $80k or less of hard money before you start thinking of your post-football career. So it is pretty slim pickings on both sides, and like you said, smarter GMs are now spending their money on the line of scrimmage instead, and offensive coordinators and head coaches - especially those who have played in the CFL before - are constantly maximizing the motion and waggles of their wide receivers and slotbacks before the snap.
You'll still see good-to-great QBs get paid handsomely: Chad Kelly *ptooey* at age 30 is about to get $600k a year. Fajardo (32) and VAJ (31) were at $400k, Maier (27) and Brown (27) at about $350k, et cetera. If Rourke (26) comes back up north, he's an easy bet to take over Kelly as the highest paid player in the CFL. If Ford (26) and Powell (25) take the reins in EDM/HAM, they'll probably get significant raises to that $200-300k+ mark. Davis Alexander (25) after a few good showings in MTL for an injured Fajardo might be able to springboard himself into a starting position and a significant raise a la Dru Brown.
Collaros (35), Harris (37), BLM (34), and MBT (36) are just this generation's Glenn's, Burris's, Pierce's, and Durant's getting paid in the latter half of their career's based on their reputation of being previously great or "good enough" CFL QBs (because again, that's the only thing teams know, instead of the mystery box of their own QBs or some of the backups on other teams that are still sticking around at age 25+). At least with Collaros, one could argue that he's still pretty good, just not as good without as much time in the pocket and inability to roll out as he gets older (and WPG losing out on some key players on the OL either due to age, contract, or injury all happening in 1-2 offseasons was a recipe for disaster). Harris just needs to stay healthy in SSK - but he's old, so that's a tough ask. HAM and EDM tried to go with either of BLM or MBT for that "just give em a chance" and have an egg on their face because of it.