How did humanity put men on the moon before somebody thought to add wheels to suitcases?

It just seems so strange given how obvious the idea of wheeled suitcases is now, but whilst we made plans for landing on the moon in the early 1960s (not to mention the moon landing in 1969), wheeled cases weren't invented until the early 1970s (see United States patent 3,653,474 for "Rolling Luggage").