I think your largely correct about the generational issues regarding car tastes and 122 and 1800 being more revered by classic car folks. However, here in Western Washington, in particular the Puget Sound area, we don't really have the same rust issues that many experience in the east. My personal suspicion, which is a totally unverified opinion, is that something more sinister and intentional happened. Only a few (maybe 6) years ago decent and cheap 140's were plentiful and 122's and 544's were relatively rare; then the trend shifted and 140's have become almost extinct. Then again, unlike the 240 versus 740 situation you mentioned, the 140 series haa MANY parts of equal or superior quality that are interchangeable with those from earlier models, surely working against the survival of this model.