Then came a product of a quasi-obscure Japanese firm, Fujifilm, the existence of which one would normally learn about in photo catalogues . Velvia. Velvia was 50 rather than 25, was equally fine grained than Kodachrome 25, and was also much easier to process and, especially, much less risky (E-6, could be done at home or down the corner). The colour response was markedly different but, all in all, was very vivid and up in vividness to Kodachrome, which never had happened before in the industry.
IIRC in a few years Kodachrome sales had a sharp fall and the Fujifilm brand became synonym of professional material rather than Kodak. I think the risks and waste of time related to sending Kodachrome to a far-away laboratory weighted much more, in the shift, than the colour response of the two materials. Velvia was good enough, but without the anxiety.