I think the software industry is like consulting, in that there is an up and out culture as you age in the industry. The expectation is that you grow more skill

I think the software industry is like consulting, in that there is an up and out culture as you age in the industry. The expectation is that you grow more skilled by some order of magnitude as you grow older. I think the fact that pay rises exponentially with relatively low years of experience supports that idea. This presents a problem for engineers who have 10-15 years of experience but have been working on the same sort of problems in a tech stack they are comfortable in. New employers will expect them to be expert level but they simply don't have the depth of knowledge that the industry associates with their experience level. So they are unhirable and "aged out".