1. Enough computer control for reasonable efficiency

2. Largely independent computers

3. No centralized infotainment that controls the entire car (you can swap the radio)

4. Still lots of knobs and dials, no touchscreens

5. Enough computers to get pretty good diagnostics if/when something goes wrong

6. Most of them have lock clickers, maybe trunk, almost nothing else

7. Engines are older, built "heavily" and don't suffer from too much boost / high bearing load

I think the last one is a big one that the closer a car gets to say 2020ish the more you really have to look at how it was built to know what you're getting. It's great to have a two-stage oil pump to reduce pumping losses when an engine doesn't REALLY need 60psi of oil pressure at all times. But GM 6.2L V8s are grenading all over the place to save less than 1mpg and over 100kmi at say 18mpg vs 17mpg that's 5555 gallons of gas vs 5882 gallons or 350 gallons. Even at $5/gallon that's only $1750 in gas vs $10-$20k for a new engine and I can't imagine it's net-reduced emissions as there's absolutely a bunch of emissions encapsulated in that at least $10k price. This is just one example.

BTW I'm not advocating for any policy or that anyone should be forced to do anything. I'm just personally more excited about keeping older (fuel injected, computer controlled, efficient) cars running well than I am about spending a bunch of money on a new car that's got a lot of engine "innovation" in it where all the kinks haven't been worked out yet.