Why do you think I pay for flights and lodgings? ;)
But really in my family’s case flights are expensive and quickly add up to a month of their income. It’s not that they don’t want to go somewhere fun, it’s that they can’t. And I’m tired of burning all my vacations on going back home. Flying them out somewhere fun is the obvious solution.
Of my parents & in-laws, really only my father in law would probably genuinely be able to enjoy going somewhere we chose. My mother in law and parents would probably actively dislike going..
About 10 years ago I stopped trying with certain things..
My parents anniversary one year we treated them to brunch at a place that's like.. not fancy, but wear a polo shirt & not sneakers.. but also its NYC so if you don't they aren't gonna kick you out anyway. Nothing adventurous food wise - chicken, steak, burger, pancakes, fries, eggs, whatever you imagine standard fare but done very well.
It was clear they weren't enjoying it, and in a subsequent anniversary dinner they insisted we all go out to the place they chose - fried fish & laminated menus at a marina type thing.
I've found a lot of parents have trouble switching from being providers to being provided for, especially if some of your siblings are still "takers".
Personally my parents insist on us joining them on vacations I extremely don't want to go on (Orlando theme parks in peak 100F+ summer heat as 40ish couple w/o kids), and that they'll cover the expense.. when the expense isn't the issue, and 1/10th of what I'd spend on holiday.