It's kind of unfair to point and laugh at the person who didn't predict the future correctly.

If you're going to put your predictions out there in the public sphere as an influencer, then I think it's fair (in fact necessary) to judge people on those predictions and their record.

However, I doubt many of us would do better if held to the same level of scrutiny. Two examples from these boards: Dropbox ("it sucks!") and Theranos ("game-changing!") would embarass at least a few of us.