It's all about ROI. You can make a case for almost any conventional repair, save a transmission or engine overhaul.
When a battery replacement exceeds the value of the vehicle, and the one source of mechanics is incentivized to sell a new car, the economics will never make sense.
Much will depend on exactly what batteries cost in 10-15 years, or whenever the current batteries start to fail.
If they still cost $25,000, then yeah, that's probably going to be a poor value proposition.
If they cost, say, $5,000, then no problem!
If Tesla and others start selling ~$35,000 cars with 200+ mile ranges in the next couple of years, then I think it's going to be closer to the latter scenario. But it's hard to know for sure.
