In the IBM antitrust case, IBM was forced to separate their OS and App businesses. Their OS business had to publish all of their APIs and was not allowed to communicate non-publicly with their App business. This was to prevent IBM from using their OS monopoly to gain an App monopoly.

Once you are a monopoly, you can expect such restrictions.

What Google is really good at is evading FTC regulation by staying within FCC jurisdiction. The FCC has historically been hand in hand with industry. The FTC has real teeth.