The reason why we continue to hear the same predictions is because the predictions from the other side (that everything will be alright this time) are never concrete. It's always something like, "oh, there will be new industries you couldn't possibly imagine before, and jobs will be there". Excuse me if I don't find that argument convincing.

Saying that it happened before is not really convincing either, unless we understand the underlying mechanism and can predict that it will continue to operate the same - and I haven't even seen any convincing theories yet. Relying on past observations alone without understanding what's behind them is not always such a good idea; you might be crossing the river by walking on ice because it never cracked before - and then one day it does, because it's springtime. If the risks are high, I'd rather be more sure than "it never happened before". And we're talking about a potential economic disruption so massive that it'd likely erupt into violence, so the risks are high.