Bad quality article.
There's a simple answer: ball bearings are relatively high tech that requires lots of innovation to come together at the same time.
There's a simple answer: ball bearings are relatively high tech that requires lots of innovation to come together at the same time.
IIRC, the reason it didn't appear sooner was a combination of a) getting reliable castors[1] for wheels that small is a non-trivial problem, and b) there wasn't much demand for it until the 80s.
[1] These things: https://en.wikipedia.org/wiki/Caster
Is it because people flew less? Because more people checked luggage more often and carry-on was less common? Because airports were smaller?
In Victorian era, if you can afford to travel where you need luggage, then you definitely can afford people to carry that luggage for you, and those people would have been cheaper than high quality bearings that wheeled luggage needs.
It's attributed to Agatha Christie (1890-1976) autobiography that in her younger years she never thought she would ever be wealthy enough to own a car – nor that she'd ever be so poor that she wouldn't have servants; and yet eventually she was in both these conditions at the same time.
I think like the bicycle, it was just combination of factors preventing adoption - and once these had all moved, it was an obvious improvement.
e.g. The luggage you put the wheel on. My distant memories of family suitcases weren't rigid. Deformable cloth over a flexible outer band of some type. First ones with wheels I saw just had them on one bottom corner and a drag handle on the opposite top corner. Where f'in vile to use, as the whole thing would flex as you pulled (Toppling and attempting to break your wrist). They only really became 'good' when we got rigid luggage (carry on bag with extendable handle or rigid-shell case like Samsonite).
But another reason is that previously "You didn't have to move it yourself" In 'the golden age' a porter would put your trunk/case on a wheelbarrow for you. Then these transformed into 'rows of luggage carts in the airport'. Then as the decline continued 'rent-able luggage carts, you didn't have local-change for'... and at this point lack of service for your bag, crossed our ability to make wheeled luggage - and we all bought it.
There are lots of other factors though. One was buildings with lots of smooth floors & no stairs, which IIRC was partly about designing to be wheelchair-friendly, and partly about luggage carts.
Another as you say was flying becoming less of an elite thing -- the private jet people today sure as hell don't muscle their own luggage anywhere, so theirs just has to look good in the hotel room.
Another was just savvy marketing: again IIRC, the breakthrough came from marketing them heavily to pilots first, cool people in smart uniforms (who did not have porters) breezing along with smart leather bags. Precisely to break the image of old people dragging their potatoes home.
Other thing I'd meant to mention, was that the territory of "wheeled luggage" has expanded. Previously maybe at an airport you'd haul your luggage to a car at the kerb that will take you to your destination.
Modern airport usually has some public transport that takes you into town, and from there you get further transport to where you wish to go. i.e. Having your luggage be less of a burden opens up your choices.
I live in a university town with a lot of foreign students. It's now entirely normal for me to see one 'herding' (for want of a better word) a flock of cases quite successfully down the pavement infront of me.
https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/198100...
It's page 5 before it even gets to the invention of the wheel!
That said, my non-expert opinion is that a penny-farthing without ball-bearings would probably still work OK; a rover-style bike with a chain would be much harder. But the ability to make bicycle chain, and the ability to make spokes for wheels, I think these happened about the same time too.