Remember, the aggregators originally dethroned the travel agencies as the 'experts' in connecting people with what they want. Google search is in the business of providing information, meaning if they have the info available they'll provide an aggregated list of restaurants to someone who wants restaurants.
Google has a long and storied history (since Dejanews) of fucking up user generated content on google properties.
If you're looking for restaurants and hotels, TripAdvisor and Yelp are exponentially better than anything Google is going to give you.
I stopped using Yelp the minute they made their mobile site unusable in a pinch while pulled over on the side of the road. It doesn't matter how good the content is if I don't have the time to jump through their hoops.
That's the point - that these businesses are providing enough information to allow Google to aggregate them for a user with intent, rather than just pass the user off to another website aggregator.