"Should professors be forced to retire?"
https://www.nature.com/articles/d41586-026-00055-4
The data points to retirement age limits not resulting in new faculty positions at the same rate as faculty posts become available. A pungent point, since retirement age limits were justified on this basis. Further, non-academic posts (i.e., administrative and support posts) are increasing at universities. Plus:
“In many disciplines, your abilities don’t fall off a cliff at the age of 69”, says Oliver Linton.
That is true, but: our abilities often fall off a cliff *far before* that. Sometimes, even decades before that. In particular, our ability to perform research work with our own hands, and to pivot into new research lines, or entirely different fields when the present one is exhausted.
While retirement per se doesn't matter, what matters is the capability of the system to engage in new research approaches, and to explore so far unexamined questions or newly opened fields of research.
How to square the circle? Grant emeritus status to any academic who wants it, at any age. Salary stops being the university's problem; laboratory space frees up for others; and if any grant body wants to provide support funds to the emeritus, by all means; or if the research is engaging enough that other faculty members want to support it in collaboration, absolutely. The relief in voting power while retaining talent, experience, a no-fucks given attitude to questions in seminars, and often the willingness to lecture, at essentially no cost, is a no-brainer.