The article just strikes me as plain wrong in this regard. Yes, of course Apple isn't going to use OSM in the Bay Area, but it's a big world out there.
It'd likely be necessary to make that data available under the same license OSM is under, but that'd be it.
The way people use OSM, they grab a dump of the data and then load it into a database or whatever (probably processing it into a convenient schema) and then build maps from that database. So it's pretty easy to have more than 1 source contributing to the map you are displaying.
For updates, edits to OSM are available minute by minute, so if your data ingestion is up to it you don't have to put up with the stale data:
https://wiki.openstreetmap.org/wiki/Planet.osm/diffs#Minutel...
OSM comparatively was of much higher caliber, which was surprising.
According to the article, OpenStreetMaps was one of the data sources that Apple used and decided wasn't up to snuff.
The article doesn't specify what the problems were with OSM, or if there were any problems unique to OSM, but one of Apple's priorities is rapid map updates, which is something that can be accomplished faster if it's in-house.
In addition, Apple intends to update its new maps in real-time (new road opens and 100 iPhone users drive on it, it magically appears on the map). I don't think that's possible with OSM.