All of its Maps data and many of its APIs already existed for Google Maps on the desktop. Within the mobile space, and relative to a mobile-only competitor, Google's access to that data is effectively free.
Map data for mobile isn't free even for Google. Google buys licenses to the data from a few map data providers, and as there was effectively a duopoly in global map data, those licenses have very strict terms of use. To use that data for e.g. real-time navigation assistance in mobile requires a different, much more expensive licenses.
You mean it has a low marginal cost. However, it required a huge capital investment to create, from which they are now rightfully reaping the benefits.
I'm certainly not saying they are wrong to leverage that asset. I don't think the point is about right or wrong as regards Google's action, but simply the extra barrier this represents for a competitor.
