https://medium.com/dotblockchainmusic/on-music-and-shipping-containers-5bd29943678

The shipping technique known as “break-bulk cargo” was the only method of freighting goods around the globe until the 1950s. This system required deliveries of sacks, barrels and crates to be stored on the docks for days before a ship’s departure when they would then be loaded individually.

Because there was no standardized size or shape of parcels, these items were an inefficient use of surface area storage both onshore and ondeck. Loading items individually was also time consuming, so expensive labor forces of longshoremen were required to make fast work of loading the ship. Imagine moving to a new city, but loading the moving truck with each individual item from your house instead of first placing them in individual marked boxes. The load-in and load-out times would be exponentially increased unless you bribed a number of friends to help with the work.