Yes, you use taxpayer funds and volunteer trail crews. Having done trail volunteer maintenance myself on the PCT, I can tell you it works just fine. There are also low cost permits for thru hikers and trailhead parking, which offset some of the cost without creating nasty externalities like getting people lost (which is what happens when you charge for maps).
They’re not charging toll. They’ve got an outdated funding model based on selling maps, and they’re sticking their head in the sand. But what are the other options? Go to the taxpayer? Put up advertising billboards on the trails?