I think you're right on the luxury brands being less durable.
To address the second airplane example, we really have to go through all that you're buying. Namely: more leg space, faster airport queue processing, more luggage, better in-flight service. Do I value these at 3x the cost? Maybe yes.
Both me and the richest person on the flight are going to the same destination. They're not getting there any faster or safer. Everything else is a fleeting luxury.
Not saying it's a bad to spend money on temporary comfort, but it's the opposite of the Vimes boot problem.
If you are over thirty and still this strong, then you have my respect and envy. I’m not even forty and even I would say a >7h economy flight (middle seat particularly) can take about two days to recover from.
How much money would you pay for two extra days of life? In the end, time itself is also “fleeting”, if you want to put it that way. But I sure as heck would fork over the money if I had it.
The funny thing is that from what I heard with the antiques markets (which is admittedly possibly a decade or so old) it is antique luggage of all things which is 'in' and antique furniture which is out relatively speaking to the past.
The grandkids not wanting it may still apply if they are still minors, there would be plenty of time for tastes to shift again.
It’s not suitable for air travel, but I treat anything for air travel as disposable. I still use it all the time for car-based travel. It’s larger and nicer than what I fly with.
To address the second airplane example, we really have to go through all that you're buying. Namely: more leg space, faster airport queue processing, more luggage, better in-flight service. Do I value these at 3x the cost? Maybe yes.