The actual Google maps app was released and had TBT before Apple Maps even came out. The previous/original “Maps” app was using Google map tiles but was written in-house by Apple. Whatever its feature lacks were is on Apple, and Google had already delivered that feature to customers, without Apple needing to spend all that money.
Posting because it's too late to edit, but I realized later that my above comment is wildly wrong. The "Actual Google Maps app" of course did not predate Apple Maps so my point is completely invalid. I regret the error.
I still assume the overall reasons for whatever Apple and Google each did amounted to greed, greed, and more greed.