Well, she's not wrong there -- those river cruises are expensive! I'm glad the old lady is enjoying her final years on the planet. Of course, she is burning up you and your wife's inheritance, but isn't her joy worth it?

Obviously you're too young to understand. You'll get there OP, you'll get there.

I need more context to decide wheter her complaining was rational. If she worked all her life and this was her first vacation in 30 years it would still be fair to complain about the costs. Because there really is a cost to getting old but income tends to rise as well. Unless she was talking about costs other than finacial ones. Then it would definitely be correct.

You deserve it for being a kind, listening grandchild. Nothing really sucks here...

Doesn't mean the cost of old doesn't still suck..

That's why she's upset about the cost of getting old... it's cutting into her vacation budget!

That's not so bad. Well-off people can complain about money too, if they feel like something need costs more money than it should. People who does see the expensive shit they spend money on as stuff they, so to your mother-in-law her cruises are part of the "cost of getting old".

People grow up and age hearing about all the great fun things that their parents/grandparents got to do once they retired. They are usually upset that not only do they not get to retire young enough to enjoy those things as much, but because retirement isn't realistically possible until they're older, they have higher expenses. A lot of people feel like they've been lied to, and they sort of have.