Ban is a heavy word. Can Google issue command to android phones to stop running some particular program? For example as a security measure to stop malware? I think that Google have that ability, even if that malware was side-loaded. Apple definitely can do that on Macs. That feature could be abused to prevent running any forbidden program and side-load won't help you.

Android is still better than iOS in that regard, because it's open source and you can disable anything. Just side-loading might not be enough.

Funny, I was thinking the exact opposite. It’s the perfect way to isolate China from the rest of the world, and unless they start going after allies then I’ll be cheering them on.

This is also why 40%-Tencent-owned Epic Games have been attacking Apple non-stop ever since they purposely got themselves banned from the App Store to mount a PR lawsuit campaign to try to force Apple to allow third-party app installations, which coincidentally happened right after Trump signed an executive order that would ban Tencent’s WeChat.