They do, actually, but they tend to miss the point that the CN route through Brantford has little or no potential for upping passenger service - for the same reason that the CN line to Montreal is a dead end for passenger improvements. ie - freight conflict.
Much as I lament for the likes of 1983ish service through Brantford, it ain't coming back.
But now that you've got me grumbling..... I would argue that the highway congestion on the 401/QEW in the western GTA and much of the way to London screams much louder than Toronto-Montreal demand. It may not be a moneymaking market-based opportunity, but Toronto-Kitchener-London rail pax is the solution to an enormous economic cost to Ontario's economy let alone many Ontarians' quality of life. For every dollar spent on passenger rail east of Toronto, we ought to spend two on the west side of the GTA.
Having a Provincial and a National operator tripping over each other (and waiting for the other to pick up the check) is not helping, either.
I personally wanted HFR West along the GEXR sub instead of GO to London for this reason.
I wish VIA bought the GEXR and operated an HFR style service on dedicated tracks through K-Dub and to London.
GO is a more a local service, perhaps both could co-exist, but I don't have faith in GO to offer a fast service to Southwestern Ontario. Thats simply not their mandate.