The state pension argument really is a red-herring. Retirement age was 45 until 1947, briefly no limit then 60, now 65. It has only briefly and accidentally coincided with pension age
That incapacitations are rare doesn't prove this a non-issue. On the contrary it's the result of diligently applied medical standards with tests such as ECG's mandated according to age. AND a defined evidence-based upper limit.