I had a wheeled suitcase in probably the late 70s--which was an unstable wheeled traditional suitcase. (i.e. narrow configuration with a high center of gravity.

I had a wheeled suitcase in probably the late 70s--which was an unstable wheeled traditional suitcase. (i.e. narrow configuration with a high center of gravity.) Not sure why it took a while for manufacturers to reimagine to a more stable orientation. There was some parallel technical innovation--such as the wheels and bearings for rollerblades--that was going on during the 80s.