From what I’ve seen, it’s usually borough councillors, city engineers or the city that refuse to allow full TSP and intersection/traffic management. So, we end up with highly compromised TSP all over town.
To be fair, every proposal until the last one presented an underground branch to Montréal-Nord. As we know, station boxes are, by far, the most expensive component of underground rail projects, easily costing 2x-3x the cost of elevated train stations. Doubling platform lengths would have massively increased costs. I still agree than 40m platforms feel way too short. I would have felt more comfortable running 40m trains on 60m-80m platforms.