[kogus]

This comment seems wrong to me:

  There is no inherent reason why a more-expensive car should
  be better or worse in terms of reliability than a
  less-expensive car, so my guess is they’ll track each other
  fairly closely going forward.

If the metric is per car faults, then surely more features mean more opportunities for defects, given an equal attention to quality across all features?

[kbutler]

I'd say that there are reasons that both higher and lower price vehicles should have fewer defects, but it's not clear which reasons would dominate. (And probably different factors dominate in different periods of car production).

High cost: more attention to detail, higher quality parts, more care with fit and finish, should yield fewer defects.

Low cost: simpler vehicle systems, fewer moving parts, fewer unproven features, mass production with consistent processes, should yield fewer defects.

[dfxm12]

The shift is a combination of mass-market cars catching up in overall quality and less new technology in these vehicles that can increase the chance of something going wrong

Part of it seems to be that there aren't more features in luxury cars. If you look at the graph, we're seeing mass market cars getting fewer problems and luxury cars remaining relatively flat.