"Their own maps"? These are their maps. They are rendering them, they are hosting them. If you mean "their own map data", then that would be silly (& expensive) for Apple to either (a) drive a car around everywhere like Google Street View or (b) licence some third party mapping company. OSM is a good solution for Apple here.

They did buy c3 technologies so they are probably up to something map related.

I'm pretty sure they can afford to buy their own map data. What would be nice, though, is if they put the cash into fixing up OSM. Somewhat like what they did with KHTML.

Right. Because they don't have the cash to do these things. Expensive is relative.