The stations are locally-owned. Usually by a college, school district, or local government entity.
I don’t believe I’ve ever seen a local program on one
Almost all PBS stations have local programming, even in small markets. Some of them award-winning programs.
And a lot of the "national" shows are actually productions of local stations. For example, Masterpiece is WGBH/Boston (in partnership with other broadcasters). Sesame Street started out as WNET/Newark.
Some PBS stations do a good job of providing unique programming to small markets. For example, in the 90's WVIA/Scranton aired Star Trek reruns because they weren't available in that market.
[0] https://current.org/1979/02/the-nixon-administration-public-...
I suspect that you'll have a lot of stations streaming the same thing at different times.
As some others have commented, the local/national split works well for PBS and NPR. The model is similar to how local broadcast affiliates work (like your local ABC or CBS station) but is more mutually beneficial.
I can try to answer any specific questions you have, if you want.
Local PBS channels cover local content. It's the same reason local news isn't broadcast nationwide.
PBS itself does nationwide coverage of news along with creating other content, which is syndicated.
Edit: there are a number of other reasons as well, including the difficulty of coordinating national broadcasts at the time that PBS was founded. Major networks were once also primarily driven by local affiliates, with some differences in local programming. The US is a big place.
This exists[1], but it isn't PBS.
Propaganda isn't just Soviet posters describing the abundant harvest. Any widely broadcast messages with an explicit goal to influence populations, even if the messages are accurate, is propaganda.
The recasting of propaganda as "evil lies" (or "fake news") has poisoned the well when it comes to discussion of accurate propaganda, which still exists and is in use every day.
[1] https://en.wikipedia.org/wiki/Radio_Free_Europe/Radio_Libert...
Not if you frame it like that, no.