Each search costs 0.0003 kWh of energy in Google infrastructure. That's just energy bill. Now think about massive infrastructure that is out there giving you sub-second results for 40,000 queries each second all over the world. Think about the man power that does on day-in day-out to make sure things are not gamed in constant war of SEO. I highly doubt Google can function in same way without economy of scale.

Google is a search engine company that gives better results because it has more opportunities to improve the product with each request it sees.

Advertising is the same way: The more opportunities you have to try matching a person with a thing they might like, the more you'll learn.

Google is on a scale that are likely two orders of magnitude more than their closest competitor.

Hilariously, Google is by far the best at mapping local people with local businesses, as they've mapped most commercial centers, and run heavy machine learning across them to extract information their competitors can't even hope to try for another decade.