Thankfully many (not all, like POI) edits can be checked via satellite imagery [3], of which OSM has permission to use many - global ones being Bing, Maxar, Esri, Mapbox. With so much sources of imagery, the update rate is acceptable for most places.
All in all, the result is not as bad as you'd expect. From normal people I hear that OSM is "very accurate" (at least here in Europe). Oddly enough, nobody says anything about blatantly fake info, which indeed does very rarely slip, but apparently gets reverted.
Now as I am thinking, there is "validation team" of sorts, that's Mapbox data team, which uses OSMCha [4] to flag suspicious changesets and checks them (albeit not by physically going there).
[1] https://wiki.openstreetmap.org/wiki/Quality_assurance#Monito...
[2] https://wiki.openstreetmap.org/wiki/Notes
Areas with local mappers will be watched even more closely.
All in all OSM often reaches a level of detail Google Maps can only dream of. In the Netherlands the number of outright errors is really quite small, and at least everything is pretty much up-to-date. Google Maps is still showing (and routing over) a trunk road in my home town that closed over a year ago.
> A map of the world seems like sooo much work to keep updated
It's really not that bad. Major infrastructure draws the attention of people who are fascinated by highways or railway tracks. The same goes for national cycling networks and the roads and cycleways these use. Major administrative rearrangements (changes in the borders of municipalities etc.) also draw a particular group. And finally, local mappers care about their local piece of map, often down to the newest projects. As a local mapper myself I find it a joy to be the first to map a new street or add a newly assigned name to some unnamed way.
It's also a nice hobby, because you visit parts of your town to survey you wouldn't ever come otherwise.
I was linked to OSMstats [1] earlier - was fun to look through, and the "Contributor to Elements Created" ratio made me proud to be a Canadian contributor :)
Think of it like the stack overflow „tasks“ you are asked to do all the time: review this question, do this, do that ...
On Wikipedia withholding edits until review works in some language versions [2], but because Wikipedia pages are "atoms" that stand on their own, they have it easier.
[1] https://learnosm.org/en/josm/josm-conflict-resolution/
[2] https://en.wikipedia.org/wiki/Wikipedia:Flagged_revisions/Si...
And anyway real problem is a stale data - especially shops. Data that was wrong from start is rare, OSM has nearly no vandalism.
Making easier to verify data is much better idea (one of nicely working things is a StreetComplete Android app - about 20% of shops where I am asked to add opening hours are gone, so I open a note, take a photo and later me or some other mapper removes no longer existing shops)
Someone adds a street. What do you want to do to validate it? Is there some international OSM team, which goes to all the locations and checks, whether there is really a street? With Wikipedia articles it is simpler, because you can check sources mostly online or you have experts on subjects world-wide, not bound by location mostly.
A map of the world seems like sooo much work to keep updated, while many Wikipedia articles can stay as they are, if they are OK now, because they treat historical topics for example, or mathematical things. There are new developments in those areas as well, but no one will take a wrong road when driving, because the Wikipedia article was not updated. Or at least it is not likely to happen. By introducing additional barriers, the update frequency on OSM might be even lower. I wonder how many contributors there are for OSM maps. I have personally never updated a map there and have been too lazy to read up on how to do that.
One would have to find a clever way to validate map information, which does not inhibit participation.