In both cases, one should note, he nonetheless provided a personal and honest response, following the demands of politeness and social obligation that occur in small communities.
The trend in our ability to address those outside of our immediate social networks seems to be that it will only get easier as time passes. Either our idea of what constitutes polite social reciprocity will have to change, or new ways of mediating these communications will have to be found (automated prioritizing, etc).
Polite social reciprocity has changed. Many contacts are ignored outright (hanging up on telemarketers, not acknowledging job applications, not returning voicemails, etc.). Delayed responses are the norm with emails, texting and voicemails. Greetings and closings are rare unto suspicious in emails. Spam filters black/white-list what gets through. Long replies are rare. ...and little of these are ever considered "rude", as we all understand the staggering volume of messaging faced and managed, if with occasional notable failures.
Today, E.B.White would just set up an auto-reply and get on with his next book.
ETA: Right, he wouldn't as indicated. Though something would give, and some technology would be leveraged, making replies take much less than hand-typed-on-paper.
I disagree. In fact, White himself disagrees in the letter. He could have set up an auto-reply by letting his publisher handle his mail, but found that "evasive and unsatisfying".
One can only hope that there will be some kind of convergence of email, SMS, status updates, voicemail, IM, twitter, DMs, etc., etc., etc. with some kind of automated prioritization/ filtering. When it takes hours to take care of your inbox in the morning, there is a systemic problem. Hopefully some room will be left for good manners and proper English.
It then becomes interesting socially whether it is best to click a button acknowledging that you saw the email but either didn't read or read but didn't reply. Or will at always be a social norm to not acknowledge to give you some kind of out of you converse with the person in future.
The trend in our ability to address those outside of our immediate social networks seems to be that it will only get easier as time passes. Either our idea of what constitutes polite social reciprocity will have to change, or new ways of mediating these communications will have to be found (automated prioritizing, etc).