Yes, but a) life isn't all about money. If you've been at all successful in your earlier working life, then by the time you reach 81 your focus shouldn't be on
*earning* money. It should be on SPENDING and ENJOYING it before it's too late!
As you can't take it with you...
And b) as far as having a "sense of purpose" goes, there are many ways of achieving that, other than through work.
It could be using the time during your retirement to be a better parent/husband//grandfather (tick as appropriate), or just simply enjoying the fruits of your labour. For me (your dad aside, as he's obviously happy), that's a big part of the problem we have in this country:
for too many people, their work is their LIFE, rather than simply a means to an end.
It's where for me the French (and also Italians) get it right.. You can travel through huge parts of France, through small towns and villages (ditto Italy), and often the shops are closed and places are deserted, as the locals are either on a 2-hour lunch break or having a 'siesta'!
They know when to work and when to chill and enjoy the good things in life (eating good food and spending TIME with their friends and loved ones), and so they're content working just enough to pay the bills and have reasonably comfortable but simple lives, and most importantly don't suffer from stress, as a result (glad your dad doesn't). They're laidback to the point of being horizontal - and good on them! That's more my world
Here in the UK? Well, I don't need to point out how different it is (and getting worse all the time), as we've been here many times before: shops open 24/7, due to the effects of mass consumerism, and one of the worst work/life balances in Europe..... A rat race populated by headless chickens? You can keep it!!
Marco.