Nobody has thus far provided any evidence of a “botnet.”

Sometimes we aren't the boss and we don't get to see the evidence. That doesn't mean there isn't any.

Can you think of any reason a government engaged in cyberwarfare might want to ensure there was informational asymmetry? I sure can.

To me, the 'profiles on the next generation of leaders, throughout their formative years' argument is stronger than the botnet one.

I don't particularly trust Google or Apple to firewall a malicious and determined nation-state actor (0 days being 0 days), but it seems lower probability than the technically trivial data collection.