For sure a 10-year-old used car in 2023 is massively safer than a 10-year-old used car in 2003. I don't know if that can possibly explain how that 10yo used car in 2003 was $1000 (5% of 20ish k MSRP) and an equivalent 10yo used car in 2023 is $20k (75% of 30ish k MSRP - 20k inflation adjusted from 1993 to 2013). Of course these numbers are ~~vibes based~~ approximations and anecdotal, but it's kind of my impression.

I would think the safety argument is already generally accounted for by inflation - Euro NCAP, NHTSA, etc. has been going pretty strong since the 90s. I don't know if I buy that backup cameras and blind spot monitoring becoming standard in the late 2010s suddenly made cars retain all their value, because new cars got those features but the MSRPs of those cars was basically just increasing at ~the rate of inflation. Also while these cars are getting safer, they're getting much more expensive to maintain, which you would expect to drive down used car prices. It's strange for sure. The pandemic can't bear the entire blame either though, since it was a trend that started before it. 2020 just supercharged it.