This is an important concept. It's normal for ownership costs to rise as purchase price rises. The curve defines, for any vehicle in the class, the five-year ownership cost that we would expect to see at each possible purchase price. If every vehicle in the class were an average value, then all the dots would fall exactly on the curve. However, it's rare that any dot is exactly on the curve.
Some dots are a little higher or lower, and some are a lot higher or lower.
Conversely, a dot a little higher than the curve is a poorer than average value, while a dot that is much higher than the curve is a poor value. Value is a relative term, not an absolute term. It is performing better than the logical expectation. Certainly in an absolute sense. Most other vehicles cost less.