This is why I believe it should be a legal requirement for digital storefronts to have an API that allows 3rd parties to create custom UI for them. I understand

This is why I believe it should be a legal requirement for digital storefronts to have an API that allows 3rd parties to create custom UI for them. I understand that they want to have marketing control over their content, but as a result we're creating an objectively worse experience for customers with no way for competition to step in a solve it.