Ok, jobs in manufacturing have been greatly reduced over the past century and the individual productivity sky-rocketed. The consequence was consumer goods became dirt cheap and few people work at producing them - at least in the western world.
Now things start the same with knowledge jobs and some services. With a diagnostic tricorder, automatic blood analyser and self-service MRI, the doctors and many specialists at the labs will have a good part of their work disappear or be replaced by a friendly unskilled worker telling you where to place your hand and hand you the print-out. Another set of jobs on the way out are train-drivers, truckers, taxi-drivers and pilots, they have a big chance of being replaced by computers in the near future.
What will be the consequence? Will the world end? Will the mschines rise and Skynet take over?
One of the first consequences will be, that the value of the service rendered will be greatly devaluated. In the end, we humans pay manly for three things: The value of the raw materials, the necessary investments for the production site and the time spent by a human to create the product. If the latter two drop significantly, the second because the productivity of the machines go up and the third because of automation, then simple we won't be willing to pay as much for the product and spend out money elsewhere. This elsewhere is where the jobs for humans will be.
For one, personal comfort services are very often hard to automate. Hairdressers and make-up stylists will be be hard to replace by computers. As another consequence, the organisations will fill with pointless jobs which keep each other busy. We see that today with all the consultants, controllers, marketing departments, safety and security people, quality assurance, project managers, application owners and so on. Those are nearly totally unproductive or, the few that are good at their job, cost only a little less than what their work saves. This is the negative aspect, but the same also exists in positive. Skilled people are able to spend more time doing things not possible before. Today, many illnesses have been identified that before didn't have a name because people died of other things first. And for many of those illnesses, cures have been developed.
In the end, humans will go on pushing the envelope, being that with discovering new cures to make life longer and better or be that by spending more effort on hairdos and the next fashion in legging-design. Automated tasks will just become a commodity, no matter how complicated it is. If you don't believe me, just look at that mobile phone of yours and look around how many designer cases are floating around. People are willing to spend 25% of the value of the phone on a piece of printed plastic with some designer-scribbles on it.