Again, the walled garden has an exit. But why would you leave it when you have to fend for yourself outside of the walls, and everything is given to you on a silver platter within them?
Well, with Android's walled garden, competitors outside of it are not allowed to compete on a level playing field with the Play Store.
User installable 3rd party mobile app stores cannot implement automatic upgrades, background installation of apps, or batch installs of apps like the Play Store can. These limitations are designed by Google and are implemented in Android.
If the user tries to install an app on their own, they're shown scary warnings and must adjust arcane settings, but if they use Google's Play Store, no scary warnings are shown and no settings need to be adjusted. They're told they're "protected" by Play Protect, but aren't shown scary warnings about the fact that the Play Store is the main distribution method for malware on Android[1] when they go to install apps with it.
Continuing with the actual garden analogy, that's like trying to compete with the garden itself by planting your own flowers and the garden making it ugly with weeds. The point Apple and Google are making is that Google's walled garden is Android, as Apple's walled garden is iOS, and the app stores are simply features of those products, and thus to compete with them you need to compete with the entire product. And whether or not that's actually the case is currently being decided in Epic v Apple.
User installable 3rd party mobile app stores cannot implement automatic upgrades, background installation of apps, or batch installs of apps like the Play Store can. These limitations are designed by Google and are implemented in Android.
If the user tries to install an app on their own, they're shown scary warnings and must adjust arcane settings, but if they use Google's Play Store, no scary warnings are shown and no settings need to be adjusted. They're told they're "protected" by Play Protect, but aren't shown scary warnings about the fact that the Play Store is the main distribution method for malware on Android[1] when they go to install apps with it.
[1] https://www.zdnet.com/article/play-store-identified-as-main-...