[Sargis]

Google's mission is to display their ads to as many people as possible. How is a walled garden going to help achieve that goal?

[rbarooah]

...because Google left the Internet's core like it is and didn't build a walled garden around it.

The commenter I was replying to claimed that Google chose not to build a walled garden around the internet because of their good character.

If they were able to do this, they'd be able to limit the threat of Facebook and other advertising based competitors.

They haven't done it simply because they can't. Not because it wouldn't be to their advantage.