In my experience, using the Google search engine returns the Google search page that includes the Google Maps. The search results and the entire page is provided by Google and of course they will include their map in those results.
If you change the search engine to DuckDuckGo, you will see Apple Maps in those search results.
I don't see how Apple can remove content provided in the Google search results and replace those with Apple Maps. Webpages are made up of <tags> and URL's to show you the content on how the page is coded. A URL can also specify a specific app to open, which is why when you choose the Directions option provided in a Google Search result, it directs you to download Google Maps or if you have it on your device already, it will open Google Maps.
In my test I simply searched "Red Robin" to bring up the search. Without a space it will default to www.redrobin.com, so you need to have the space to bring up search results. Compare the results using both search engines. The Google Search engine also brings up the prompt to sign into Google which is annoying, when you navigate to some pages such as Trip Advisor from the search results. I don't get the Google sign in prompt when navigating to Trip Advisor from the search results when using DuckDuckGo.
