...because there's no advantage to Google in having one.
That assumes that Google exercises absolute control, it does not. Every employee, every manager, has their own agenda which may or may not coincide with the best interest of the company as a whole. And that's assuming that your premise is correct. There may well be advantages we can't see from the outside looking in. Unless you're privy to all their spreadsheets you can't assert that simply because it appears to you to be true.