Mass transit sounds utopian but is mostly nonsensical to Canadians who live outside of the few big cities and understand how goofy it would be to put thought into it. Toronto and Ottawa and Montreal don't represent the rest of the country, but unfortunately their voices steer policy in ways that don't serve the rest of the country very well.
Buses are a thing of the past in Canada, they're far too slow and the countryside is too spread out to make feasible routes. They also used to cost almost as much as a plane ticket and take 10x the time. When intercity lines outside dense population centers DID exist they were pretty much empty all the time, hence their extinction.
High speed rail could only serve major centers across the country. Other than the Toronto to Montreal corridor, population centers along the rail lines are too far apart. For example the distance between Toronto Ontario and Kenora Ontario is roughly 1500+km, so a high speed rail trip would still take 6-8 hours between them at best. The train would be mostly empty too because there's just not a lot of people going between non-major cities. It's not like just because a rail line appears between places people are going to start going between those places all that much more. There's just no way the operation costs for high speed rail would be covered by fares from a handful of people.
Air transportation is only good for longer trips between two major centers in Canada. If you're going to/from
smaller regional centers for most of Canada the commercial airports don't even exist, and if they do the flights are infrequent and the costs to fly in/out of them are absurd and the flights might even take far longer than just driving. For example to fly between Kelowna BC and Kamloops BC, a 150km drive, costs $300-$500+ for the ticket and takes about 5 hours (not including travel to/from the airport, check-in time + waiting at the gate + waiting for luggage) due to a stop in distant Vancouver. It's just not feasible to airlines to have short direct routes, so they don't. But again you're not going to find airports with commercial flights for about 90% of the towns in the country because the towns are small and don't have airports (except if they don't have roads to connect them like in the north).
To summarize, unless you don't go anywhere or you're only going between Toronto-Ottawa-Montreal by train or flying between distant cities or in a remote village, you're likely going to want to use a car otherwise the alternatives can be absurd.
Buses are a thing of the past in Canada, they're far too slow and the countryside is too spread out to make feasible routes. They also used to cost almost as much as a plane ticket and take 10x the time. When intercity lines outside dense population centers DID exist they were pretty much empty all the time, hence their extinction.
High speed rail could only serve major centers across the country. Other than the Toronto to Montreal corridor, population centers along the rail lines are too far apart. For example the distance between Toronto Ontario and Kenora Ontario is roughly 1500+km, so a high speed rail trip would still take 6-8 hours between them at best. The train would be mostly empty too because there's just not a lot of people going between non-major cities. It's not like just because a rail line appears between places people are going to start going between those places all that much more. There's just no way the operation costs for high speed rail would be covered by fares from a handful of people.
Air transportation is only good for longer trips between two major centers in Canada. If you're going to/from smaller regional centers for most of Canada the commercial airports don't even exist, and if they do the flights are infrequent and the costs to fly in/out of them are absurd and the flights might even take far longer than just driving. For example to fly between Kelowna BC and Kamloops BC, a 150km drive, costs $300-$500+ for the ticket and takes about 5 hours (not including travel to/from the airport, check-in time + waiting at the gate + waiting for luggage) due to a stop in distant Vancouver. It's just not feasible to airlines to have short direct routes, so they don't. But again you're not going to find airports with commercial flights for about 90% of the towns in the country because the towns are small and don't have airports (except if they don't have roads to connect them like in the north).
To summarize, unless you don't go anywhere or you're only going between Toronto-Ottawa-Montreal by train or flying between distant cities or in a remote village, you're likely going to want to use a car otherwise the alternatives can be absurd.