It's natural for people to work longer. People are living longer than ever, health care is better than ever, etc.
65 Was the standard retirement age for decades. Not unusual to see people wanting to work now at 70-75 years old, and they are still quite able and competent.
Love this forum and plan to retire a few years early myself, but I also see quite a few postings on here about people planning to exit the workforce in their 30's & 40's with a pretty small nest egg. Some will be fine, but I think many are in for a rude awakening, will be near broke and forced to go back to work in their 50's and 60's just to get by.
You also have to consider that many people really love their jobs and enjoy going to work every day. Why shouldn't they stay in the workforce longer, if they want to?