Two other factors that aren't coming up in this analysis are long term maintenance costs (highways in Ontario are constantly being resurfaced) and land use opportunity costs (it's simply not viable to run six lanes of freeway into most CBDs, and doing it with grade separation leads to raised highway eyesores or insanity like Boston's Big Dig).

In any case, as others have pointed out, we don't have to argue hypotheticals here— China, Japan, France, Germany, etc have all shown that frequent-service electrified passenger rail is perfectly possible and an incredible public good.