[ubernostrum]

Google has a dominant position in search. Google also has lots of other businesses offering different products and services. Maybe those other businesses really are the very best in their respective markets, maybe they aren't. In a proper market, we would find out which is best from seeing them compete against other companies' products/services, and the need to out-compete other companies would drive quality up and prices down.

What actually happened was that Google removed the need to compete with anyone, by always listing its own other businesses up-front in search results. Since Google has the dominant position in the search market, this guarantees a steady stream of customers to the other businesses, even if they're not as good as other companies' products/services, and means they don't face competitive pressure. Without competitive pressure, quality doesn't get driven up and prices don't get driven down.

Since we want competitive markets to drive quality up and prices down, we have laws which don't allow a company that dominates one type of product/service to use that as a way to achieve dominance in other products/services by avoiding the need to compete.