>On the other hand there will be a very large portion of society who will become obsolete with absolutely nothing useful for society to do.

Almost everyone has something to contribute. The problem is that society structured in a way where most forms of productivity are undervalued. A great example of this is art. Nobody in their right mind could imagine a world without art yet there's the stereotype of a starving artist. Burger flipper robots aren't going to make or break the world.