Sure you do. New technologies are new and do new things. So far, there hasn't been problems with mass unemployment. But looking into the far future, when robot

Sure you do. New technologies are new and do new things. So far, there hasn't been problems with mass unemployment. But looking into the far future, when robots are advanced enough to do the basic labor of growing food, building homes, doctoring, shipping stuff around, etc. It's not super clear how much you'd really need human labor at that point, which could easily mean mass unemployment. Of course, with the right societal design, mass unemployment could be a perfectly fine thing.