So just for what it's worth... Production of live sports is incredibly expensive for broadcasters and just not worth it unless you can charge really high ad rates. When TSN radio didn't get the last Jets rights, it was actually considered somewhat of a win, because they could still do the Pre/Intermission/Post stuff, and not have to worry about carrying the cost of the broadcast (which MOST people are watching on TV anyhow).
So anyhow, for TSN... They can't charge high ad rates for the pre season broadcasts because there aren't enough people watching... And without the high rates, they can't afford the broadcast. And, no, even if you wanted to say "well if they did a better job then maybe more people would watch!!" people just wouldn't... It's pre season CFL... As much as we diehards love it, there's not that many viewers. Not enough to make it worth their while anyhow.
And yes they are the league's partner so they are supposed to take some risk to support the league but they're still a business and it has to make business sense for them to do anything.