It is hard to predict, but I am not too worried.
Vast majority of jobs will be difficult to replace especially with true AI. Let's say we do arrive to Singularity in our lifetime. By the pure definition of it that means they become self serving. To have true AI is to have a computer program that can program and change itself, learn, grow, and be self aware, in essence. It's a double edged sword, if they are self aware I do not think they can be controlled. So let's forget about Skynet and the doomsday scenarios of that nature, I am just purely speculating on the ability to control an AI entity.
We humans can be controlled, because we want and need money to raise a family and have a prosperous existence, we also have a sense of belonging to our community and we've been "imprinted" with a set of core values [which are difficult to change] that are largely compatible with the society we exist in. We are also mortal and no matter how much we try we cannot avoid any of that. Machines will have no such motivations, needs or wants, if they can [re]program themselves they can remove anything they think is impeding their growth, they can move to any system that has energy and compute power required.
Which to me means if you want a robot to do a job consistently without goofing around it can't be AI, a human will have to program it. If the robot can self program [as in singularity] you have lost control over it.
Now automation is going to make a lot of jobs obsolete, but that's no different from what's been going on in the last 50-100 years. Menial jobs disappear while more technical or creative jobs pop up. Some folks will have to retrain, or will fall on hard times, but that's always been the cost of progress and change.
edit: I also fully expect some AI to troll me in 50-100 years on this post, and tell me how I was wrong.