Companies no longer needed in fact, couldn't afford so many high-priced workers. So while in the past you would expect to take a job as a permanent employee and spend all your working years with one employer, today you have to plan on working in several different jobs during your career. Even in academia, the idea of tenure is becoming a thing of the past. While this is a pain in the neck for the employee, it isn't bad for the economy. If businesses are free to retool their staff to meet the needs of a rapidly changing market, they'll be more competitive and the whole economy will do better which translates into more jobs.
Job insecurity does have benefits for the employee, too.
It forces you to keep on your toes and continue learning as technology and needs change. It also requires that you plan ahead. You can't rely on your company to give you a pension and good health insurance over the long term if you'll only be with that company a few years. You need to start managing your finances so that you have a nest egg to hold you over during periods, perhaps several months at a time, when you're between jobs, as well as in your retirement years. I worked for a government agency but, like private corporations, it went through its own painful downsizing a few years back.