[someone123]

By the way, people sometimes mention that Vancouver doesn't have much commuter rail but there is the West Coast Express. It is operated by TransLink, the regional transportation authority.

Without TransLink to operate this service, what are the odds that VIA or some other federal level agency would have stepped in and set it up? What would Toronto have if there were no Metrolinx and VIA were the only potential operator?

We cannot know for sure but for whatever it's worth, my take on it is that very little would have to change in a parallel universe to end up with no commuter rail at all in those cities and that, if it didn't exist, people would treat it as something exotic and unproven. To some degree this is the world many other metro areas or provinces are stuck in, where there is nobody to champion regional public transportation goals.