WhatsApp has been required to provide an open API, Apple has been required to provide alternative app stores. Neither one has actually done it because the EU is too pussy to enforce the law, but the legislators clearly had no huge principle disagreement when writing these laws.

Mobile networks have been forced to allow roaming in other countries for a certain low fee, and that is actually enforced and has happened. It's clear the EU has no qualms about forcing companies to do business a certain way when it serves some greater interest.