The context of that prediction were the extreme records set by sea ice in 2012, when it did almost disappear. That made some scientists think that we were seeing a nonlinear phase shift and that it would not recover. It did recover, and resumed its linear downward trajectory.
But if your takeaway from that is that scientists are overconfident and wrong, that is insane, because the important thing to know about sea ice is that at its yearly minimum, its volume is a third of what it was in 1980. No matter how you cut it, it's almost gone.