The problem Apple's walled garden is that they don't mainly use criminal law but technology to protect it. Nothing really keeps you from legally jail breaking your iphone, but it's a painful process and staying up-to-date is a constant cat and mouse game with iOS devs.
Only competition law can force them to open up properly.
"Garden" is marketing jargon to beautify the reality of things.
Think of the word Garden, fruits, vegetables, flowers. That word was specifically chosen by their marketing team for a reason.
The reality is that Apple has dictator-style control and the ability to ban/punish people with no oversight. "Garden"...yeah words paint prettier pictures than reality if you let them.
Only competition law can force them to open up properly.