Well, here's the response:
These questions are impossibly difficult for emails. He should call.
I think you're in Australia so if I hear anything else I'll let you know to save you the monster phone bill.
I understand Wendell has a problem with emails, Steve - but that is a pathetic response for a corporation in 2020. Shirley there are others at Magnepan who are happy emailing (younger executives, say)?
I don't want a discussion on their thinking 25 years ago - so to me, the answer to my question is one sentence - eg:
* (as Liz suggested) we made the length different to try to stop people swapping over ribbons, as we felt that would negatively impact our sales of new 3.X spkrs.
This is a perfectly sensible business decision!
Or:
* our technical department made calculation of the length of ribbon required to deliver 3 ohms - and we didn't think of the impact on old ribbon owners.
I don't believe this possibility - as changing ribbon-cage lengths would've had a manufacturing impact ... which would've cost time & money.
Anyway - colour me disappointed.

Andy