500 kph is too much, but 250+ kph high speed trains surely proliferated nicely since then, at least in the Old World.
Even Uzbekistan and Morocco now operate high speed trains, and a high speed connection of the Baltics into the rest of Europe is being built.
(It is a bit weird that the New World as a whole is so bearish on HSR. For example, a Trans-Canadian high speed rail would connect all the major metropolises in a single line, as most of the Canadian population lives close to the US border. At the very least, a Toronto - Ottawa - Montréal - Québec line would make a lot of sense. Further west the terrain might just be too unforgiving.)
The terrain is sort of difficult in the Canadian Shield, but it gets easy in the prairies, and then very difficult as you head west into the Rockies. I think the bigger problem going north and west of the Quebec City/Toronto corridor is the sparse population.
With a single line, you would also need to choose between serving Edmonton (like the CN mainline) or Calgary (like the CP mainline). VIA rail currently skips Calgary even though it's the bigger/faster growing city.
Really, you need at least 3 lines because you also have to go both north and south of Lake Huron. And that's not even getting into Atlantic Canada.
Looking at the Canadian population density map [0], the Windsor-to-Québec line seems to be hitting the sweet spot for having enough people, and the total distance of about 1000 km between both ends would fit into the pattern as well.
Edmonton and Calgary would require two lines, yes, and quite long ones. These may be already too far away.
Population density maps alone will always lead you astray when it comes to building things like HSR if you don't also map in the terrain. It's not super challenging to build light frame buildings and asphalt roads on steep grades, marshes, curvy river valleys, frozen tundra, or even cliff faces. It's much harder to build train tracks, factories, skyscrapers, and other heavy buildings in such places.
A lot of people can live in a place it's where it's difficult to build traditional rail, let alone HSR. Also places where HSR might work can be filled with people and existing construction which you can't always just uproot for rail.
Some countries that built extensive HSR networks (Italy, Spain, Japan) have a lot of challenging terrain.
If you travel, say, from Rome to Florence by Frecciarossa, the line goes through six galleries of total length of some 40 km.
Human settlements are a bigger challenge. People don't like to be uprooted, and small communities along the way don't benefit from HSRs, so they have an incentive to oppose them.
That accident happened long ago, on a testing track, due to bad signalling/communications, leading to maintenance equipment still on the tracks, and the maglev running into that.
Even Uzbekistan and Morocco now operate high speed trains, and a high speed connection of the Baltics into the rest of Europe is being built.
(It is a bit weird that the New World as a whole is so bearish on HSR. For example, a Trans-Canadian high speed rail would connect all the major metropolises in a single line, as most of the Canadian population lives close to the US border. At the very least, a Toronto - Ottawa - Montréal - Québec line would make a lot of sense. Further west the terrain might just be too unforgiving.)