Perhaps it is too simplistic, but the alternative Apple chose suggests hubris. I suspect that TomTom or Garmin or even OpenStreetMap would have been glad to partner with them to develop an app to replace Google Maps. Instead, Apple chose a homegrown solution, quality be damned and then threw TomTom under the bus when Maps was released half baked.
The decision to adopt not invented here as corporate policy backfired. Forestall was probably prescient enough to see where it was headed.
The problem is I can just as easily come up with a situation where Google is being "evil" and doing everything it can to screw Apple:
Apple and Google have become serious competitors. Apple realized that and started working on its mapping solution, but recognized it wasn't ready in time for iOS 6. Unfortunately, the license was going to run out before iOS 7, so a new contract would have to be negotiated[1].
Google came back and said "piss off" (or "pay $50/phone" or whatever "evil" terms you want). Apple couldn't make the terms work within their constraints, so quickly made a deal with Tom Tom and tried to integrate their data into the nascent mapping system[2].
The iOS 6 beta comes along and the data is nowhere near where it needs to be. Apple has a decision to make here and, with a choice of "go for it" or "pull a major feature in iOS 6.x"[3], they decide to cross their fingers and go for it.
Now, iOS 6 release hits. They know the maps aren't ready, but the bridges have been burned. Their choices now are "put some lipstick on a pig" or "pull a major feature from iOS 6.0". They decide on lipstick. Sometimes you get away with it; sometimes you don't. They didn't.
I'm not saying this is what happened!
My point is that when major companies are in "coopetition"[4], nothing is simple and obvious. Maybe Apple thought they could shroud everybody in a reality distorition field. It is possible, even plausible. I just don't think it is the most possible scenario, and it is tiring to hear it expressed as the "only" possible solution.[5]
3. iOS releases seem to have stabilized on an October time-frame. Based on my experience, it is unlikely that you could pull up the release of an OS by 6 months, so maps would have to change in a "dot" release.
5. Regardless of what really happened, I would have loved to be a fly on the wall in those meetings. Those would have been awesome bizdev meetings...unless Apple really did say "piss off". :)
The "Apple dumped Google" meme was started by Apple fans before the new maps got released. You can go back and read the triumphant proclamations of how much better the new maps was going to be now that the nasty Googlers where no longer holding them back that were written all summer.
If the new Maps had even been good enough they'd still be saying it. Instead they're now trying to backpedal, just like before Maps was widely believed to be a bit shoddy it was claimed to be an Apple "homegrown", from scratch data set, when clearly they mostly just bought in data, but still managed to screw that up by putting some pretty crappy business info on top of solid map data. Now the emphasis (and blame) shifts onto all the data suppliers whereas before they'd all have remain faceless (just like Gorilla Glass wasn't allowed to name Apple as a customer, and Samsung has to screenprint Apple logos onto their chips).
The decision to adopt not invented here as corporate policy backfired. Forestall was probably prescient enough to see where it was headed.