Below is what I extracted from a survey:

"Affluent individuals are more than twice as likely as other people to keep working in retirement, according to a July survey by Bank of America, Merrill Lynch and Age Wave, a research firm based in Emeryville, Calif., that specializes in aging populations. Some 33% of retirees with $1 million to $5 million in assets are working, as are 29% of those with more than $5 million. While many people struggle to figure out if they can afford to retire, most affluent individuals who are working do so because they want to, not because they have to, according to the survey."

So I guess the mid-50 guy is typical of the affluent segment who are still working because they want to not because they have to. The survey though done in the US, probably holds true everywhere.