I think most executives could post a coherent and informed response online (with some notable exceptions), but older and more established companies tend to have layers of lawyers and PR specialists in between the CEO and the public.
True. Some could do it but almost always self-censor or are censored by their minders, and some truly are full of nothing but hot air. A lot would probably be capable of it if they actually had total freedom, though I'm not sure if it's most.
I wonder if the correlation might be age, since it seems to me that younger people try to avoid bullshit and seek out authenticity (giving or receiving) moreso than older generations, which were embedded in more traditional business models across all industries. (I could be completely wrong about this being related to age or generation, though; totally guessing. Authenticity does seem to be a universally growing trend.)