Email was never a threat to mailed letters or magazines

Excuse me? You didn't put a /s in there, so I'm genuinely puzzled by your comment. If it was sarcastic, then well played.

Granted magazines have died out because of websites, but letters?

As a Dane unless you have an exemption, because you're very old or intellectually challenged, then you're required to have a special digital inbox for government and banking. When that was in introduced, letters died in less than a decade. To such a degree that the postal service stopped delivering letters last year.

A private company took over the letter carrying responsibility, so you can still send a letter. But there are no mail boxes left, you have to go to a store that does packages as well and standing in line to send a letter. The private company btw did a splendid job of making the postal service seem competent in comparison. Something no Dane would have found possible in years prior.