How was this handled in the age of typewriters?

How on earth did English typography get so weird with mdash, ndash, dash, hyphen, etcetera while most of the readers have no clue about the the differences. IMHO, just use dash.

Can you explain me how the different lengths of dash add to the understanding of the text, when I usually don’t even see the difference on my mobile phone screen?

cheese sandwich

Nevada city, California. Population 3k+. Thanks to my wife’s addiction to christmas movies.