Absolutly correct, but there is also much more too this, there is page layout and look. There is speed of results depended on ability to trawl and return answer

Absolutly correct, but there is also much more too this, there is page layout and look. There is speed of results depended on ability to trawl and return answers. There are complimentary platforms holing to their ecosystem. There is information they have access to only known to google from past searches or alternate platforms. There are masses of manual non algorithmic overrides. There is simple inertia of typing Google into the address bar for many. Yes giving up the source algorithm would be a loss. Google have seen this coming for years and have been building the moat so even this information shared wouldn't really help a competitor take any significant chunk of their business in the short to medium term.