High speed is a big thing. And actually high speed, at that. A massive number of trains are very slow and even a number of "high speed" trains are not even remotely as high speed as they could be, with proper investment. It's hard to replace planes when we're talking at least twice the travel time.

I'd love to have more train options in Canada. There is a train that spans the width of Canada, but it is so slow and deprioritized that it's not actually a viable means of transit across Canada. You can fly Toronto to Vancouver in a little over 4 hours. So maybe 6 hours with the airport overhead. By train, it's 4 days. That's something you'd only do for the experience and it'd be a significant part of the trip (one person I know who did it said that they wish they utilized more stops along the way, because by the end of the trip, they were getting pretty sick of it -- despite the fact that they recommended it glowingly). With a high speed rail, that could become less than 1 day trip, making it a lot more feasible (a lot of people already view the day they fly as a day spent only on travel).

And that's an extreme. Getting around southern Ontario is far more common and practical (it's an extremely population dense area). But the trains we have for that are very low speed and have mediocre schedules (sometimes only good for commuting). Even though a train is an option, I often find that the bus is actually the fastest way to get to my destination, cause the train is so infrequent and really not fast.