Not always - volume is often better than margin if you are in a competitive market and have enough access to capital (other things being equal).

Particularly if you are taking market share from your (higher margin) competitor. If you can sell two cars at half the margin, that can be better than one car at double the margin if your competitor got the other sale, assuming your strategy is to take the market (i.e. wipe out your competitor).

High margins tend to be hard to defend in the long run (without building a moat).