Small American towns used to have train stations, even in the middle of nowhere. They enabled factories and other industrial work. Then the trains would go away, and the factories would die, or it would happen the other way around. Then teenagers would go out to abandoned tressels to have bonfires and drink near the scenic decay every weekend, until the cops showed up to scatter them running into the woods.

True, but only in the east coast and Midwest. Even at the peak of US rail (1916) the west coast was only sparsely connected.

… it was also only sparsely populated

Have you ever looked at a rail map?

California and Indiana both had a population of about 2.7 million in 1916. Indiana had a dense rail network and California didn't. Indiana is only ~5x smaller than California.

This is what the rail network looked like in 1916:

https://etc.usf.edu/maps/pages/4400/4401/4401.htm

The less dense areas are impassable mountains or inhospitable desert

Thinking of "too small for a station", whenever I passed through Dovey Junction I was only able to see one building, on the other side of a river, and it appears that there is literally no road or path to that building.

https://maps.app.goo.gl/Wx98GRYpPaRbrcRg6?g_st=ic

"junction" is pulling the heavy weight here. The station is right before the tracks branch, so the purpose of the station is probably to let riders transfer from service on the one branch to service on the other.