Photo Engineer
Subscriber
I'd say it's a feedback loop; the effect feeds back into the cause, sending Kodachrome sales into a downward spiral. This also makes it difficult to say what's the cause and what's the effect, since both factors function as both cause and effect.
Also, even a few decades ago, Kodachrome had to be sent out to one of a handful of facilities for processing, whereas E-6 (and earlier Ektachrome processes) were more easily done locally. This would give a speed advantage to Ektachrome -- not as great an advantage as exists today, but a real one nonetheless. Once some other factor (improvements in E-6, decline in film sales generally, UFO thought-control rays, or whatever) causes a dip in Kodachrome sales, the aforementioned feedback loop would take over.
I have stated before that Kodachrome sales began slipping in about 1990. Fuji dropped out of Kodachrome type film production about then in favor of the E6 style Fujichrome.
Yes, it is a downward spiral, but when customers don't want the film in spite of having good processing service (1990s, remember), then it is a sales argument, not a processing argument.
Also remember that Kodak had a new family of Kodachrome ready to go in the late 80s and could not get any interest in the market place or amongst the editors who got samples. Even the Kodachrome 400 was a ho-hum item to everyone contacted.
PE