That's more a mass production thing isn't it - we had trolleys of various forms you could load your bags on to.
Strong plastics, probably made such mass production cheap enough.
People rich enough to have wheeled luggage in the past would have just used servants, it's seemingly economics rather than technology that prevented such "inventions" as attaching wheels to things permanently instead of temporarily.
A modicum of googling suggests Templar Knights had wheeled trunks in the 12th Century though.
I'm surprised this article didn't give some credit to the Americans with Disabilities Act, which is a main reason there are ramps you can use with your wheeled luggage instead of hauling it up the steps to a building entrance.
Strong plastics, probably made such mass production cheap enough.
People rich enough to have wheeled luggage in the past would have just used servants, it's seemingly economics rather than technology that prevented such "inventions" as attaching wheels to things permanently instead of temporarily.
A modicum of googling suggests Templar Knights had wheeled trunks in the 12th Century though.