If we're going to simplify or generalize, I would simplify McDonald's to being a "sugar and salt" company. Those are the cravings in the human brain that it satisfies.

But yeah, I agree with you. Businesses are more complex than individual touchpoints.

Google is a ad company who uses search to attract customers.

I don't see the McDonald's reference as the same, drinks are part of their food product. Ads are not a integrated part of search (google did not start out having ads).

Sure they are - that is what separates AdWords from other advertising platforms.

So, if set up a fashion magazine and then I fill it with ads, I'm in the fashion magazines business, or in the ads business?

If someone asks, which of the 2 answers would be more helpful to them?

If your magazine starts handling ads in every other publisher's magazines too and then starts handling ads in TV and then starts putting up billboards by the highways, I'd say the answer isn't so obvious.