I can imagine someone (probably hipsters) making it popular again in the next few years.
They would say it is relaxing to write letters, and it will become a new trend like colouring in. It can be seen as a craft, so there will be letter writing kits with nice paper and different types of pens. It will make people want to improve their handwriting or learn things like calligraphy/brush lettering, as well as improve their spelling.
Another good thing they would say about it is that it will make people's days better when they receive a letter that isn't a bill and they know someone was thinking about them and went to the effort to write and send a letter to them.
There would be nicer looking post boxes everywhere, and some might be animal shaped.
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Your neurodiverse (Aspie) score: 152 of 200
Your neurotypical (non-autistic) score: 70 of 200
You are very likely neurodiverse (Aspie)
AQ: 40
RAADS-R: 149