>>684074Isn't that mostly how work works in capitalism though? More or less?
We also have the problem that new technologies, social change, etc, might mean there is much higher demand for a certain field in 2040 than 2020. Even if you train the next generation to fill those vacancies, the situation might change again in 20 years so those workers would have to retrain regardless.
Maybe we are missing the point of what OP is asking. What point are you trying to arrive at? I feel that the idea of a world where nobody changes jobs is so outlandish that it could only exist in a thought experiment.