The root of the thread IS returning and how people do it WITHOUT becoming destitute. money ON the dock. You address only the CRUISING part, not returning at 80.
Here's a fresh cruising scenario. This couple (age: low to mid 40's), no kids, quit their jobs in the UK to take off on their( paid for) 34' stout cruiser. They had some $ stashed away for emergencies.
They both owned homes when they met, and after marrying, they lived in one and kept the other as a rental investment.
To cruise: They vacated and rented their own home and put each residence in a typical property management service in the UK.
They were gone for nearly 4 years, sailed over 30,000 NM between the USA, Canada, the UK and the Caribbean and South America.
They were on a tight budget (we got to know them quite well). No dockage, very rarely a mooring, very few restaurants, etc. But they ate and lived well, kept a boat plowing mile after mile. That is a hefty expense compared to just living on a boat.
For the most part, they lived and cruised on their income from those 2 properties.
Upon re-entry to the UK(this past year), they moved back into one of their houses. With their income now slashed, they both found jobs in the fields they left(quite a feat - they must be good at what they do).
They are one good model(no one size fits all). Real sailors, they wanted to cover ocean miles and spent little time in any one place. They wore out a suit of sails(a hefty expense) and had a couple costly repairs but still stayed on about a 25-30k / yr, budget, for nearly 4 years.
Their re-entry was smart. They didn't lose financial ground by cruising this way at this point in their lives, and their adventure was beyond priceless. They've put the boat on the market and I'm quite sure their plan is to work for a few years - buy a larger boat - and do it again.
They liked Maine so much, they sailed twice to our area from Caribbean winters. We did some coastal sailing in company and got to show off our coast.
Here we are in Frenchboro(Brits on the left), having a lobster dinner,...that was on us.