Earlier quoted context omitted.
And for missing search. And for missing social. And for insulting OEMs. And for his failed Windows Vista launch, and Windows 7, and Windows 8. For one man, he sure has a lot of failures on his plate.
So has Steve Jobs missed social and search as well? No. All companies need not do the exact same thing. Missing mobile is relevant because it is eating into Microsoft's PC revenues, but social and search is a whole new business that Microsoft didn't need to get involved in at all. In my view, Ballmer's mistake is to not go after Oracle and SAP much more than chasing Apple and Google.
Edit: Apple did acquire ping, but that was social music, which is a bit different. They also introduced siri, which simply plugged in to preexisting search services (Google in iOS 6, Bing in iOS7) so it really is agnostic on that front.