Higher productivity and other such benefits are a leap. I don't think it's unreasonable to assume that people who work at a company longer end up more capable of contributing to that company.

In some ways this could even be an argument for the cause of enshittification of everything. When everything is liminal, it somewhat directly leads to a 'get mine and go' type mindset, which in turn leads directly to enshittification, no longer term than next quarter thinking, and so on. I've always assumed the cause of this all was MBAs, and I still think it's the primary cause, but perhaps we're creating this certain from multiple directions all at once.