The concentration in western towns has been studied by geographers as an interesting phenomenon. There is another factor less known, but important for rail or bus demand: people travel further for services. When the number of passenger-miles is considered, rather than boardings, you get a different picture than the usual.Oh, I think the Pioneer is a possibility...and it would certainly make my life easier and more interesting.
But I just wanted to show how the settlement pattern is different in Eastern Oregon and Washington. Especially for rail enthusiasts (and other people) whose main experience is east of the Mississippi, someone might hear about "rural Oregon", and they are going to picture it like places on the Crescent or City of New Orleans or even the Empire Builder between Minnesota and Chicago...basically, places where "rural" means a town of 10,000 people every 20 miles. So this video hopefully shows what it looks like when there is a town of 500 people every 50 miles. A quite different scenario.
Although, it is possible that this actually makes it better for rail---in the Great Basin and Rocky Mountains, often times people actually live more concentrated, with uninhabited areas in-between, rather than smeared out in little towns.
One clue is the broadcast coverage areas for sports:
https://www.denverbroncos.com/news/broncos-radio-network