If they have a great meta-search algorithm, users would be able to search without an account and see how great the results are. Then, when a user wants to personalize ranking and block sites, they can create an account.

I always assumed that they make you create an account to track search usage and cut you off once you hit the free tier limit.

Uncharted and Last of Us are first party Sony games. If they were to say that a game can still be enjoyable without cutting edge graphics no one would want to buy the latest PlayStation iteration.