Balkanization is about right. In my experience developing driver assistance systems, there are enormous efforts spent on political turf wars instead of proper design and engineering.

This is not surprising, as the team structures, at least as of a few years ago, were traditionally set up with tradtional manufactirng in mind, around parts and control modules, while the functionality exploded (within 1 or 2 generation of cars) and crossed those boundaries without adequate processes in place properly architect the interactions from a bird's-eye view, creating major computing power, network bandwidth, and most importantly to OEMs, cost bottlenecks.

And as cost is king, nobody wants to budge on increasing cost on their own module, and critical architectural decisions aren't made as much as put off until there isn't any other choice left except to hacking in the most critical bits with one eye closed and hoping somebody else's jenga tower falls first.

That, I imagine, is how you get that GPS time thing, I can see how it all started: "Oh, I can save $.30 on my module if I don't put in an RTC, that'll get me a nice bonus for cost saving, GPS is going to have one anyway ..."