> It’s not like there was a shortage of people needing/wanting parts
The problem here is you get a lot of different parts from a single stolen car. Steal 10 Honda Civics and you might be able to use almost every part from the first car, but by the 10th only those parts you have 10 buyers for are valuable.
The equilibrium is a function of the number of cars people own and the percentage of mechanics willing to use stolen parts. So even if a handful of people can steal an arbitrarily larger number of cars the limiting factor is mechanics willing to use stolen parts. Total number of mechanics scale with number of cars, but the percentage of those that are criminals can vary through time.
On the car thing, I think you made some good points. I regret dragging us down this line of argumentation which has been pretty strained, though informative! You were talking about light crime in general, and I voluntarily picked cars. That was pretty stupid. Anyhow, it's been fun meeting another impassive argumentative data whore. May our kind spread! And may we disagree again, soon!
[1] - https://en.wikipedia.org/wiki/Capital_punishment_in_the_Unit...
Similarly on the car stuff, I do agree with you. You can't strip cars for profit unless there's a minimally large number of people using cars, but we were obviously well beyond that point by 1980! 80% of households had cars! It's not like there was a shortage of people needing/wanting parts. That's far more than enough to create all the sort of venues necessary to be able to comfortably resell parts.