But Apple is using other companies to get the data from, how many people do these organizations have working on maps in total?
You don't understand the point. Google is using other companies' data too. Open google maps in your browser, try scrolling around various parts of the world and look at the lower right-hand corner. You'll see copyrights of various global and local companies and agencies, who provided the data. But in addition to all the data they buy, they also have 7000 people working full-time in house. Which is around 6900 more than Apple has.