Never happen. If it's a Democrat idea then the GOP won't support it just because. If it's a Republican idea they'll demand that it be entirely private sector, and totally ignore the reality that if this sort of transit was a money-maker then the private sector would have done all sorts of high-speed rail in North America decades ago. And the Democrats won't go along if it's either all private-sector or if the public has to inevitably bail it out after the private owners want out after losing far too much money.
North American politics don't have either the pragmatism or the basic understanding that some times things still have to be done even if there's no profit to be made. We're, and I include Canada too in being just as blind and trapped in ideological thought as the the Americans are, not long-term thinkers about most things the way that wiser people in place like Japan and parts of Europe are.
While I agree with most of what you've said, a big reason it happened in Europe and Asia is because of much higher population density. When you have an area half the size of Alberta (Japan) with four times Canada's population, it's far more cost effective to build such things - plus far less room for roads. That's why in Japan they build up, not out like here. Same with Europe - most countries there have far higher density than we do too.
The only places NA approaches Asia and Europe in that regard are the oldest parts - the US East Coast and central Canada.
edited for spelling...