I think the crux is those who have the financial means to retire. A 60 year old who has not been as lucky as others may well need to stay till 65 so that they have a chance of a decent retirement.
Personally I do not think the age has a relevance, in fact the opposite it many ways. An older person may need those few short remaining years to top up a pension where possibly a younger possibly financially shrewd or financially independent individual may well already have the means, be they 40 or 60. It could be argued that a 35-40 year old has plenty of time to investigate a new career, an option a ‘poor’ 60 year old doesn’t have.
Drawing a line in the proverbial sand at an age that you feel fitting, is myopic.