They might think it costs less, but I argue that's misleading. You need to factor in the mistakes, the longer training, slower adaptation, inefficiency, and a client's growing dissatisfaction with the product because of it all.

I don't think it's misleading. Companies know mistakes cost money and experience doesn't always associate with better productivity.

Most companies don't have a inkling of how to actually measure productivity.

To be fair, neither do most employees. It's a hard problem.