ABC/NBC/CBS/Fox/Etc are big corporations that produce (or commission/license, it gets...weird) shows to be distributed on their affiliates, that, depending on the city you are in, can be owned by the network OR another company that operates it like a franchise. Their affiliate agreement governs how much of the network programming they play -- though there are other agreements for non-network programming -- Jeopardy/Wheel of Fortune, for example, are syndicated and NOT network.
PBS on the other hand is more of a consortium of public TV stations around the country. Shows that you might think of as "PBS Shows" are actually produced by these individual stations and then distributed to other stations that want them. Even PBS Newshour and Washington Week are produced by WETA in DC.
Radio gets even more complicated. Many of the shows I've seen referenced on this thread aren't even necessarily NPR. Marketplace, for example, is American Public Media, which is sort of an outcropping from Minnesota Public Radio.
So funding going to ACTUAL PBS is a tiny part of this. What happens to the money going to various stations? What happens to the grants to produce and run these stations, especially in rural areas?