Sadly, you're asking why the GTAA does or does not do something.
Nobody's been able to figure that one out yet!
As to why things are the way they are in Canadian terminal buildings, here's one you'll like:
In Calgary, a new wing opened about a year ago which is dedicated to WestJet flights as Air Canada whined long and hard about wanting the horseshoe. Prior to 911, the new viewing area within the terminal gave a fantastic view of the inside of the horseshoe and now all that can be seen (sort of) are Air Canada tails. More later...
Anyway, in the new wing which is quite long and now being used exclusively by WestJet, a horizontal escalator/travelator (I don't know what they're called - moving sidewalk, whatever) was going to go pretty well the entire length of the new wing. Well someone over at AC
whined that they didn't have an equal length moving sidewalk on their side so WJ couldn't have one in theirs. And that's what's happened. Half a moving sidewalk.
Epilog - that great view once to be had of the horseshoe and all those teal tails has been forever obstructed in a significant way by "enhanced" security walkways/walls etc installed since 911.
Just thought this was a cute little story about how airport authorities in Canada can think/act. A lot of it is in reaction to complaints from a dominant operator at that airport.
Mind you, that's just an opinion