Are you ignoring that a train with a capacity load of 400+ is better than 10 buses??
Congratulations, you’ve successfully identified the inherent strength of trains, which is its scalability, where you can add cars to transport hundreds of people! This is called “Economies of Scales” and works in favor of the train in busy corridors (like the Quebec-Windsor Corridor), where large cities are within a reasonable distance and linked by rail infrastructure which allows travel times which are competitive against driving or the bus.
Unfortunately, outside the corridors, cities are smaller and much further apart, while rail infrastructure is much slower and with less sidings, which is fine for freight, but kills any chance of being competitive against most sorts of road passenger transport. In such contexts, a bus service with 3 runs daily offers 21 departures per week and thus much more utility at a
lower (!) operating cost than a train which only operates three times per week.
Have a look at the tables I posted from 1988 and see how many of the VIA services which got discontinued in January 1990 had less riders per departure than a intercity bus has seats (maybe 80, i.e., 20 rows of 4 seats each?):
- Toronto-North Bay: 73
- Halifax-Saint John: 67
- Halifax-Yarmouth: 65
- Mont-Joli - Quebec: 54
- Moncton-Campbellton: 45
- Sherbrooke-Montreal: 34
- Moncton-Edmundston: 33
- Cochrane-Kapuskasing: 12
2 discontinued services (Halifax-Sydney and Toronto-Havelock) had just over 80 passengers, but remember that even operating two buses is much cheaper than a single train (not to mention that some passengers usually get off before the last passengers board the train or bus).
In short: capacity for hundreds of passengers is only useful where you have anything close to that many passengers willing to ride your train at the particular times where you operate…