There used to be a blog post about how much an assistant professor should be willing to pay for an AER. Consider this ballpark estimation: a single solo authored AER will give your tenure at a German uni for sure: this means at least 5000k € per month until you die (mashing together pension and salary here which is conservative as the lower pension occurs later). This puts you around 50k euro net annually. Approximating the NPV for a conservatively high risk free rate of 4% and with approximately 65 years still to live yields 1.142 Millon € which are 1.4 Million $ in PPP terms.
Is the marginal value of the marginal AER decreasing? It might be non-linear bc of superstar pay.