>Used cars buyers aren't typically considering what the cost of a replacement engine is when they're buying.

That's because engines, properly lubricated, and run at a set RPM (i.e highway miles), have a lifespan that is far in excess of what a normal person would reasonably drive in half their adult lifespan. Dependent on brand, of course. But plenty of people racking up 400k-500k miles on original engines. That shit used to be unheard of back in the day.

Engines degrade by use. This is not the case for lithium ion batteries based on the way they are used in electric vehicles. Degradation is based on DoD - depth of charge. You cycle a lithium ion battery between 50%-60% instead of 10-90%, and you increase the lifespan exponentially. It's not linear. It's exponential. If automakers wanted to, they could add 2k to the wholesale price of the car, make the battery pack 20% larger, cycle the pack in a more narrow window of its capacity, and if age wasn't a factor, no battery pack would fail before the 20 year mark. Unbalanced degradation with age, as it is, is virtually the only reason every battery pack fails.

When you have a prius, and your battery pack fails, all the places that sell refurbished packs do it by taking the battery packs apart, finding the one cell thats shot, replacing it, and magically the whole battery pack works again. Why is it that one cell out hundreds? It's not as if that one cell was charged or used more than the others, they are all in series/parallel. The car charges all the cells the same. That particular cell just degraded faster than the others. The technology currently exists to make lithium batteries that last 20+ years, but it is nigh impossible to predict that during year 17, cell #345 is going to degrade 0.0032% faster than its peers and will cause the whole pack to fail.

Almost 100% of priuses will need a battery replacement by year 15. It averages from 9-15 years, with the peak happening 12 years from manufacture. Oddly enough, on the PriusChat forums, there was someone who tabulated this but cars that spent most of their life in Canada and Northern states trended toward lasting longer than cars down along the gulf coast and in southern states. Not sure if there was a large enough sample for significance, but I'm sure with the sheer about of priuses that have been sold in the past 20 years, this can be figured out.

First gen Leafs don't sell very well for exactly the reasons you mention, but the TCO for the 3rd or 4th owner of a vehicle is hard to calculate regardless. 10+ year old cars end up needing major work like a valve job or a timing belt, or some emissions thing if you're somewhere that checks that. Battery packs aren't alone in having this lurking unseen potential cost. Most Americans can't just absorb $1k+ of work to keep their car running, even if the engine is technically fine and could last another 200k miles.

If your argument is that EVs won't take off because fresh batteries aren't cheap, I mean, you're right, they're not. The refurb battery market is huge though. Instead of paying the dealer a couple grand for a brand new pack, Uncle Joe or the local cheap mechanic, and YouTube University can do it, often for as cheap as couple hundred, with practice. Plus less waste for the environment.

Given the millions of EVs already sold though, and the various EV-only mandates globally, I think it's moot because they're already here, unlike 3D TV which had no such government mandate. The average used car price from a dealer in November was $31k, and a 2012 Tesla Model S can be had for around that much (Nissan Leaf even less than that), so I think the electrified future's already here. Just gotta let it percolate out to the rest of us.

You could be right though, I don't have a time machine :) It's just EVs are so stupidly much easier under the hood. No PCV valves, no carb or fuel injectors, or O2 sensors, no emissions crap. There's still some complexity, but it's just not the same.