So far the used car market for EVs is fascinating. Right now the mean "first owner" life of an EV still seems to be triple that of an ICE vehicle. An average EV owner is keeping the car for closer to 9 years compared to the 3 year average turnover of ICE vehicles that has been a used car market staple for decades. (A lot of used car dealers would hope this statistic would decline as we have moved past the earliest of early adopters to more "mainstream" buyers, but so far there are no indications of this shifting.) Because of that EVs are holding their market prices more stable over time than ICE vehicles as they age and there's a lot fewer EVs on the used car market to judge any clear statistics just yet.
The market prices may seem to be reflecting that overall reliability of an EV is much higher than comparable ICE vehicles as they age and that so far battery degradation hasn't been a market issue. Though again, that may still be some bias from much, much smaller sample sizes to date.
What we do know is that of the EVs entering the used market, very few show noticeable signs of battery degradation (again, at 9 years on average!). Most of the ones with very noticeable battery degradation are Nissan Leafs. Most of those are still getting resold at decent prices (compared to equivalently aged ICE vehicles) and as cars to new owners (often as a second commuter car for a household some of these statistics suggest) and expected to still be on the roads a surprising number of years even after "noticeable degradation".
Some of the earliest of these degraded batteries were still under lease from Nissan, as Nissan for the first few years of Leaf sales had a battery lease model, and Nissan hasn't released statistics but admitted "surprise" that very few of the leases have been called in and most people still prefer to drive the Leafs as-is "degraded battery" or not rather than release the batteries to secondary usage. Nissan had plans for a project like Tesla's PowerWall for secondary life batteries (only; Tesla sells PowerWalls built from entirely newly sourced batteries), but claims so far they've yet to receive back enough batteries to build a single one even given how notably "degraded" their batteries have as a reputation in the used market.
All of which is to say that current indicators are that EVs seem to be on the road with their original batteries right now statistically for 15+ years even most of the "most degraded" ones the used market has seen to date. Replacing the batteries hasn't seemed to be an issue that has manifested yet in the used market. Though that extra reliability currently seems to come at a cost in the used market for the people who rely on cheap used cars because the cars seem likely to remain more expensive than ICE vehicles as that first owner statistic alone likely keeps the prices compared to age higher, but the overall reliability also may be keeping the prices high.
The market prices may seem to be reflecting that overall reliability of an EV is much higher than comparable ICE vehicles as they age and that so far battery degradation hasn't been a market issue. Though again, that may still be some bias from much, much smaller sample sizes to date.
What we do know is that of the EVs entering the used market, very few show noticeable signs of battery degradation (again, at 9 years on average!). Most of the ones with very noticeable battery degradation are Nissan Leafs. Most of those are still getting resold at decent prices (compared to equivalently aged ICE vehicles) and as cars to new owners (often as a second commuter car for a household some of these statistics suggest) and expected to still be on the roads a surprising number of years even after "noticeable degradation".
Some of the earliest of these degraded batteries were still under lease from Nissan, as Nissan for the first few years of Leaf sales had a battery lease model, and Nissan hasn't released statistics but admitted "surprise" that very few of the leases have been called in and most people still prefer to drive the Leafs as-is "degraded battery" or not rather than release the batteries to secondary usage. Nissan had plans for a project like Tesla's PowerWall for secondary life batteries (only; Tesla sells PowerWalls built from entirely newly sourced batteries), but claims so far they've yet to receive back enough batteries to build a single one even given how notably "degraded" their batteries have as a reputation in the used market.
All of which is to say that current indicators are that EVs seem to be on the road with their original batteries right now statistically for 15+ years even most of the "most degraded" ones the used market has seen to date. Replacing the batteries hasn't seemed to be an issue that has manifested yet in the used market. Though that extra reliability currently seems to come at a cost in the used market for the people who rely on cheap used cars because the cars seem likely to remain more expensive than ICE vehicles as that first owner statistic alone likely keeps the prices compared to age higher, but the overall reliability also may be keeping the prices high.