I think they should have bid until they won it. This company has billions and billions of dollars, and they absolutely need every mapping company they can get right now.
That's not how Apple do business. They only buy a company if there is a clear direction for it to improve their products.
How would Waze have helped Apple's Maps exactly? It would only add another enormous dataset which needs to be integrated. Integrating all of that data is one of the biggest challenges Apple faces in improving its Maps, so it's not clear that just adding more poorly-fitting data would have helped.
I don't think Apple's going to buy it's way in to good Maps data. They have a huge number of devices moving around in the real world, which is an enormous resource they haven't properly used yet.
For example, they could use location data to work out the most popular or most important locations and emphasise those on the map, correct roads, etc. They could also integrate Facebook check-ins (or something similar, like Foursquare) and use check-in data to improve their own POI database.