Do they really use OSM data? A few years ago we travelled in the Puna de Atacama region in Argentina, where most roads are just dirt tracks in the desert. Despite the zone being very sparely populated, most of the tracks are properly mapped on OSM. We used maps.me to have offline OSM maps (don't even dream of mobile Internet there, unless you use a satellite connection), and they proved to be very accurate. In most places, Google Maps wasn't even showing the presence of a road...
About ten years back, a friend of mine devoted his spare time to mapping on OSM. Once every single local bike path was added, he started adding roads to North Korea based on satellite imagery. Folks just like making maps, even in places Google can’t make a buck.
