Using your analogy, you're basically saying the games that sell the best are the best games.
No, it's exactly the opposite.
To continue my analogy, I DON'T claim that the person who runs the fastest is the "best person". But he is the best RUNNER. The two has zero relation to each other.
Likewise, the game that sells most is not the best game. But it is the BEST SELLER. The two have zero relation to each other.
Actually, if you insist that the games you consider the highest quality should be the best sellers, YOU imply that quality and high sales are supposed to be related to each other.
For example, my favorite game from 2009, The Path, that is an indie European "artsy-fartsy" game, that probably sold a few thousand units.
This game is probably the best thing that happened to me in the past years, yet I wouldn't claim that it "deserved more sales".
Because it's a miserable failure as a business product. It totally lacks mainstream appeal, it wasn't advertised at all, it is not actually entertaining, and it wasn't ever intended to be financially successful, the artists totally lacked serious financial considerations.
It just wasn't a strong runner in the sales race.
Therefore saying that it should have sold more is like saying that my mom should win the Olympics because she is such a good mother.