The point was that, for most users, Google is an abstraction over URLs, just like DNS is an abstraction over IP addresses.
E.g., if they want to get to Dell's website, rather than typing "dell.com" into the URL field, they type "dell" or "dell computer" into the search box and then click on the first result.
So a reputable DNS service that did this automatically would be a direct threat to Google.
User A: Google DNS: search for dell, dns lookups; dell.com, chat1.us.dell.com, checkout.dell.com
User B: Non-Google DNS: search for dell