He didn't predict the cloud, he basically predicted that the way things were then (timeshared system with dumb terminals) was the way it was always going to be. So he wasn't predicting anything, it was already there. You might be able to say that he predicted it would grow to have terminals everywhere but that is more just looking at normal growth if you assumed the current way of doing things is the way it would always be done.

We're not catching up, we're going back to it. Just this time we have dumb terminals just as powerful as the server that is doing things but relegated to doing nothing but displaying markup. It wouldn't surprise me if cost of the terminal compared to the cost of a central server at the time factored into his views.

The man was amazing, it is not often that one man can make such a impact on the everyday lives of so many, but in this case he missed where computing was going. Oddly, his creation of the mouse made personal computers more accessible to everyone.