But that's the rub, we the taxpayers have paid for all the map creation, even the new high resolution ones with far greater accuracy, yet we're stuck with these older, lower resolution and likely out-of-date maps. Even the new maps should be public domain.
* US Geological Survey: https://www.usgs.gov/core-science-systems/ngp/tnm-delivery
* National Park Service: https://mapservices.nps.gov/arcgis/rest/services
* US Forest Service: https://www.fs.usda.gov/visit/maps (the API access is further down that page).
Those linked above typically available through a standard API (Tile Map Service), as well as ESRI's moderately well documented REST API for accessing shapefiles and features. My one complaint about this data is how the USFS manages their data. In that case it seems each service region defines how data should be made available, so you have a pile of different methods for accessing things like road/trail features, or points of interest (in many cases, it comes down to "fetch this pile of ZIP files").
Then you have cases like the Ordnance Survey in the UK where apparently a lot of the data is neither freely available to the general public, nor paid for by the general public.