Who has a Social Media Officer? The secretary writing letters had a much easier job. — Elaine Scott
Not sure that's true. Letters couldn't deal with the first point anyway so I assume the comparison is with general information distribution. Then and now the text had to be written anyway, so it's just distribution.
Instead of addressing say 20 Envelopes, putting a copy in each and posting them for tower correspondents to deal with, he/she sends a single copy to the towers mailing list.
Alternatively, to cut out the middleman he/she sends a copy to the members mailing list, or if it's a large document sends it to the webmaster who puts it on the website, and then sends the link to the members list.
I don't think any of those are more work than the piles of envelopes, and most of them get more directly to the members.
What if you don't have towers or members making lists, or a website? Get them!