This seems like a pretty fundamental failure on Google's part. The whole value proposition of Google is that they'll find you the best answer for you search, not just 'an' answer that could be misinformation. This is the problem with the way their ranking algorithms tend to favor information aggregators. It's easy for second-hand sites to out-rank the source of truth. It reminds me of the way Pinterest has degraded the Google image search experience by polluting the results with their own low-quality entries.

Now I get that automating the gathering of this information must not be easy. How do you verify the legitimacy of any one page claiming to be the site for a restaurant? What I don't understand is how Google can see that sites like Grubhub are exploiting the ranking algorithm to re-route users, but they don't do anything about it. Why don't they penalize those sites?