It is no doubt a campaign or at least a meme. It seems basically impossible for everyone to have overhired, for the simple reason that qualified workers do not appear and disappear from nowhere. There is a population of qualified workers in the software sector, and only new grads and retirement can move the needle significantly. So, if someone overhired then someone else must have done without, all things considered. The only ways out of the pool are basically retirement, career change, and death.
I know there are complications with this argument. For example, unemployment could double by basically doubling the average time to find a job. That kind of thing could support an overhiring thesis if the unemployment rate in tech got very low. To really test the "everybody overhired" thesis, I think you need to do a full accounting of early careers people, unemployed, retired, etc. I'm not gonna attempt that...
I know there are complications with this argument. For example, unemployment could double by basically doubling the average time to find a job. That kind of thing could support an overhiring thesis if the unemployment rate in tech got very low. To really test the "everybody overhired" thesis, I think you need to do a full accounting of early careers people, unemployed, retired, etc. I'm not gonna attempt that...