Switzerland has 8.9 million people & can fit into BC about 23 times. BC has yet to reach the population of one Switzerland.
https://en.wikipedia.org/wiki/Switzerland#Largest_cities
Unless BC claims to have a different set of physics than that of CH, mountains can't be used as an excuse for limited urban growth & density.
https://en.wikipedia.org/wiki/Transport_in_Switzerland
Italy & Japan also have plenty of mountains, but that hasn't prevented them from proper planning & infrastructure development.
https://www.mylifeelsewhere.com/country-size-comparison/switzerland/netherlands A very flat country with about double the population of CH.
