People don't travel much in those places. During the summer a lot of them are almost completely cut off, though there's often small aviation flights from some of them, so people can get out in emegencies. The situation is a lot better during the winter with https://ru.wikipedia.org/wiki/%D0%97%D0%B8%D0%BC%D0%BD%D0%B8... (ice roads), that's how and when most travel/supply trips happen.