I understand the financial need for a higher retirement age, but I also wonder about the viability of a single retirement age. Doing some jobs that are physical

I understand the financial need for a higher retirement age, but I also wonder about the viability of a single retirement age. Doing some jobs that are physically taxing is quite different from my comfortable desk job. Maybe this is where disability aid comes in? On the other hand my mental ability night decline and now I'm simply unemployable and wouldn't qualify for anything but unemployment. Such a hard and nuanced topic.