[ZeroGravitas]

As with everything in OSM, it depends on which country you are talking about. For example, I believe in (at least some areas of) France the outline of every building has been imported from a high quality government source with address data yet the roads still have to be drawn in from satellite photos or GPS traces.

The US is the home base of Google (amongst other big name tech companies) but it's OSM data is amongst the worst. This is ironic as much of the open data used to map the rest of the world was provided by the US government e.g. NASA radar topography and Landsat photos.

But for the lower level data the best source (often the definitive source e.g. for administrative boundaries that aren't physically present on the ground) is government data, so the quantity and quality of data varies as you cross state (and sometimes county) lines.