It seems they wanted to be Google Maps but failed. You raise a very interesting point with OpenStreetMap - just like WebKit, Apple could just have put some of their billions into boosting that effort, I agree that this would have been way more productive, especially given how engaged smartphone users are with their maps.
Not sure what you are saying with the comparison to Webkit. As Webkit only became what it is because someone actually took Apple to task over the Khtml (K as in KDE, used to power their Konqueror browser) engine license.
And even then the first response from Apple was a plain source dump with zero documentation on the changes they have made, that made it basically impossible to roll the changes back into Khtml.
Would not surprise me that this was one of the reasons Apple went to work purging GPL licensed code from their offerings.
