Windows Phone: Nokia Maps, Drive, and Bing Maps

I just picked up a Lumia 920 this evening after my Samsung Focus finally gave up the ghost, had it since launch and was a total trooper. The only thing that has thus far turned me off about this switch is the weirdness of HERE Maps, HERE Drive, HERE Transit, and Bing Maps.
From what I understand HERE Maps provides the same function as Bing Maps (plus it includes mass transit info) but doesn’t integrate into search results. HERE Drive does turn-by-turn spoken directions, which is nice. HERE Transit is apparently for transit only, but isn’t it kind of covered in HERE Maps already? Bing still integrates but if you don’t grab the launcher it is always hidden away in the search function.
My question is two fold, first off why couldn’t MS have combined all this functionality into one app instead of the mess of 4 it is now? Secondly, what seems to be the most efficient usage of this amalgamation?
The reason I love Windows Phone is because it attempts to integrate and simplify tasks but this quadruple map app conundrum feels like a step backward.
TL;DR Why aren’t HERE Maps, HERE Drive, HERE Transit, and Bing Maps all merged into one super-app? What is, in your opinion, the most effective and efficient usage of these apps?
For that fact, why are LiveSight, CityLens, and Scout all different? Simplify and add lightness.

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