Why should it have been different with a Google maps app shipping with iOS?
Because the world of business development is very different from the world of consumer APIs. In a bizdev world, you want SLAs and contractually understood definitions of how both sides will behave. A company like Apple (or Google, Oracle, Microsoft, etc) isn't going to build a core feature of its product on somebody else's technology without understanding exactly what that means.
Is there any indication, anywhere, that Apple had to pay Google for the maps app? Quotations, citations? I really really doubt it, if anything I would expect Apple received money from Google for the privilege of being the preinstalled maps app.
Because the world of business development is very different from the world of consumer APIs. In a bizdev world, you want SLAs and contractually understood definitions of how both sides will behave. A company like Apple (or Google, Oracle, Microsoft, etc) isn't going to build a core feature of its product on somebody else's technology without understanding exactly what that means.
And all of that costs money.