Even where people retain jobs they are doing more.  I was a manager in a global company, 20 years ago I would have had a PA to do all the dull paperwork like booking travel, doing my expenses, filtering my mail, typing letters etc.  Now you do all that yourself, its all provided through easy to use technology, that you can do yourself on the move.
The problem seems to be that not only is that full tome PA job gone, but as a manager I'm fulfilling parts of other roles too, and much of it out of hours meaning I was working significant unpaid overtime.  Then there is the mental exertion of switching through so many various tasks.  So technology has allowed business to load up a few people with ever higher loads of more complex tasks.
The concept of the full working week needs to be adjusted, so that more people each do less.