They’re not _that_ new anymore: the original Model S was sold in 2012. So, while they’re still young compared to ICE cars, we still have at least a decade of data on them.

I do agree, though, that there’s some novelty risk but (a) my numbers only include gas (and I’m not factoring my solar savings in at all because I ran the numbers before I installed solar) and (b) I’m spending quite a bit every year to maintain my Odyssey and basically $0 to maintain my Model 3 (only exception is I’ve changed the tires once, but I’ve gone through a couple sets of van tires in the same time period for a similar total expenditure). I think that I’d come out ahead even if I had to replace the battery (or sold the car when this is needed). Also, the depreciation on my Tesla over the last four years is much more in my favor than the van’s depreciation in the same time.

And those old Model S cars have had high battery replacement rates, often at relatively low mileage.

The 3 and Y seem to be doing better, as well as S/X after 2016, but those are still fairly new.

Although, there’s a question of under warranty vs. out of warranty replacement here: replacing the battery under warranty doesn’t really add to the TCO; also, I assume the battery packs across the Tesla models are similar enough that newer cars incorporate the learnings from older models.