The answer is "no". We are not going to work longer. There is no need for our labor, since the US has a surplus of workers, while jobs are being outsourced and automated. Working-class people wear out, as do many who sit at a desk. You get to the point where you want to do something else with your life besides going to work every day, especially if you get little satisfaction, or money, from your work. After 50 few employers want to hire us. We can't compete with younger workers, especially if our work is physical. 

Many of us who are retired contribute to society as volunteers, doing something we actually care about and are good at, instead of what people are willing to pay for, which also helps keep our minds active. As a volunteer you can limit your effort to what you aging body can handle.

What Samuelson is really about is cutting the payroll taxes that pay for Social Security and Medicare, so that rich people can make even more money. Not something us common folk should support.