It's like saying Burger King offers "the best" food, because it's popular.
And there's not really a reason(besides a little bit of money) for Google, The global monopoly, to insist on doing that. It's not that hard to have an easy option for quality content.
For example: Google's forum search, which was cancelled.
Not really; no-one goes to Burger King because they think they are getting the "best" food. They think they are getting convenient, affordable and quick food. You certainly could argue that Burger King is enormously popular because it is very good at offering those three attributes.