The App Store should have worked this way since day 1.
From Jay Peters at The Verge:
Apple Cannot:
- Impose “any commission or any fee on purchases that consumers make outside an app”
- Restrict developers’ style, formatting, or placement of links for purchases outside of an app
- Block or limit the “use of buttons or other calls to action”
- Interfere with consumers’ choice to leave an app with anything beyond “a neutral message apprising users that they are going to a third-party site”