I have yet to see any manufacture come out with a battery replacement program that is economical. Look at Prius as an example, battery goes out in one of them it is basically totaled from a economic stand point unless you DIY the replacement with "unauthorized" batteries. I believe the Chevy volt is the same way
Internal combustion engines however have no problems lasting for 10, 15, 30+ years if they are maintained. I know many people that have cars over 15 years old.
It is yet to be seen how long battery packs of different design will last. Or if the drive to get more and more range out of these battery packs will push mfg's to squeeze more range sacrificing longevity as competition in the past increases . That is going to be a problem.
This planned obsolescence model we have for cell phones, to cars with shorter and shorter product life spans is not good for anyone, not the environment, not poor people that generally depend on older used cars which makes electric uses cars at ticking time bomb...
the solution can not be "just replace your $40-$60K car when the battery dies like your iPhone" that is moronic