Say some people manage to design machines which can build stuff a whooping 20% cheaper. Because it's an obvious thing to do, you'll have all the factories in the country switch to these machines, and fire a majority of their workforce. Now, on one hand you have a 20% increase in productivity and on the other hand you have 50% unemployment.
You don't have greedy capitalists making money: most of the 20% goes to the consumer, thanks to the competitive market. The biggest share of the money probably goes to the machine builders, but they earned them fair and square: they innovated and thanks to them the job can be done better, easier and cheaper. But overall you still have huge unemployment.
So what is the answer? The answer is a shift in the workforce away from manual-jobs. Simply put, continuous education. It's a fact of life that almost nobody is truly safe in this day and age. Not programmers, nor prostitutes. We could all have our jobs innovated away from us. But this is only a bad thing for those who let the current job become the sole means of paying for the mortgage.
African countries should start to worry - the time when the development goes from
commodities -> manufacturing -> development
to industrialize your country is coming to an end. In most African countries there are no industrial development (taking advantage of low cost labour). The economy is commodities& subsistence farming.
How many typists did word processing software automate out of their jobs in the 80's? Easily tens of thousands just here in the US. What are those typists doing now?