He told me that a round of lay-offs was coming and he had to stay at his desk until 9pm. He was afraid that if his manager didn't see him at his desk, he would get axed. He returned to class once the lay-offs passed. Even those who aren't laid off don't have it easy. Many of my students have seen their incomes reduced by 30-40 percent.
Lifelong employment is exactly what it says.
Once a company hired a person, they worked for that company for life. It was impossible by law to lay off employees. This does not mean that you always did the same job. Remember that the chaebol incorporate many different companies. In fact the corporate culture simply does not allow employees to switch companies.