The blog post I linked to above specifically addresses this (https://daringfireball.net/2012/09/get_the_fainting_chair). The specific consequences of delaying Apple Maps would have been either:

1. Not having turn-by-turn directions on Apple Maps, arguable the single most important feature for a mapping app.

2. Share more of Apple users data with Google in order to support Google Latitude. (https://en.wikipedia.org/wiki/Google_Latitude)

So we have two choices: Not have the single most important feature in a mapping app, or violating one of the basic tentpole features the iOS brand, user privacy. So obviously they went with the third option, launch their own mapping service despite its flaws, and I've never heard a convincing argument that that wasn't the best choice.