Ballmer doesn't get it
Saying that the PC market is dead because tablets are taking over is like saying that the oven market is dead because electric kettles are taking over.
Kettles are good for preparing hot drinks and pot noodles, much better than an oven, however they are completely at for example making toast.
Tablets are good for reading things, watching things and looking at things. Much better than the PC, unless you happen to be sitting at the PC when you want to read, watch or look at the thing. Tablets are completely useless at inputting things into the system if you want to type more than a couple of words.
For example, if you work on the road, a tablet would be good for looking at your job list to see where you need to go next, to tap on a few buttons to let the people back at base know you've completed the job, and maybe enter a few words or tick a few boxes to say what you found and what you did. If you need to prepare a report of more than a couple of sentences, then you probably want to get out the laptop to do it. If you are back at base scheduling the work, and entering notes about what needs to be done, then you will do that on a desktop machine, not a tablet.