I find it interesting, in this case at least, PG appears to be talking against the wisdom of crowds.
Now I'm not sure if he is correct in this instance, but it's probably a good idea to keep mindful of both sides. Sometimes a small elite can be better positioned to make the call, and other times it's the crowd.
Regarding the WhatsApp deal, perhaps Mark knows better than the tech community, given the large information asymmetry at play. However the reverse could also be true too, especially in companies with visionary leaders. IOW, one could question how much 'towing the line' happens at FB, given a leader with a large ego footprint.
Looking back, Microsoft missed the internet boat in the beginning (allowing Netscape to dominate), and as a result needed to play catchup. But, I'd wager Bill Gates's own limitations of judgement and inward focus on Microsoft, was a large contributor to this blunder.