Terminal decline suggests a zero end state.
Can you really see that happening?
I would imagine the decline will start to slow soon until a sustainable level of mostly advertising mail, some business mail and a tiny fraction of social mail is reached.
Terminal decline, ie reaching a state from which it will never recover.
I reckon in say, ten years time the letter situation will be unrecognisable even from the current situation let alone from fifteen years ago. Business and mailshots are in decline as other ways and methods are used.
As you know yourself some of the early "decline" wasn't really a decline anyway, It was simply a move towards a more professional auditing system rather than the old way of "well that looks like 10,000 items so we'll add 10% just to be on the safe side".
I don't know any such thing. How operational staff choose to guesstimate inter-office mail etc (for whatever reasons they may have) isn't relevant, as the amount processed ( ie the
real stats, down-loaded and gathered every day and sent to Head Office) is counted down to the letter by the machinery processing it (as has been stated on here many times before) and clearly the decline is both real and continuing. Some M/Cs are even removing under-used letter processing machinery when even five years ago they would have running flat-out 24/7.