You don't necessarily need a walled garden. A walled garden is the centralized "store" where you _have_ to download apps from. But you can still have proper se

You don't necessarily need a walled garden. A walled garden is the centralized "store" where you _have_ to download apps from. But you can still have proper security features without centralization. Android's permission system, or even some form of isolated per-process virtualization/sandboxing can go a long way. If properly architectured, it can be possible to prevent a good bunch of malware.