If you're willing not only to download sideload apps but also to modify your device so you can have root access, then it works. So not really different from Apple.
You don't need to get root on an android device to sideload apps, unless the app has specific functionality that requires root. You don't need to break anything about the system or your warranty. Its just a toggle in the settings menu.
This is absolutely not the case. I can install any app-store app I'd like, and it can install apps on my phone. I can even download raw apk file and install them myself.
Any features that require root would still require root if installed from the Play Store. That is not relevant to the argument that you can always install things blocked from the Play Store by getting them from other sources.
Moreover, the ad blocking features you get without root are a strict superset of the features that are possible at all on iOS.
> It is relevant, because if it were a free platform you'd be able to do this kind of thing without circumventing the system software.
You can do it without "circumventing the system software." Unlocking the system partition is a supported operation. Then just install a program that lets you run other programs as uid 0. This is not possible for normal apps to do because running as uid 0 means you are no longer subject to the permissions system.
Also, it's irrelevant because the whole point is that Google can't block the user from running whatever apps they like by blocking the app from the Play Store. Requiring root access is orthogonal to Play Store availability.