When I read the title, I could imagine someone at Nissan thinking "the battery is 10-12 years too reliable, can we make it cheaper so it doesn't outlast the rest of the car?"

This sort of "value engineering" is quite common today, especially since things like advanced computer simulation can make it easy to design the lifetime of a part within a surprisingly small tolerance. Before that, manufacturers would often err on the side of overbuilding to avoid premature failures.