My wife bought some slide boxes at a thrift shop today, complete with a collection of slides.
Included are some Kodachromes and Ektachromes from someone's vacation, and by luck there were two of roughly the same scene.

In general, the Ektachromes look faded and off-color compared to the Kodachromes which look near to perfect. Red has survived pretty well in the Ektachromes, but the green and blues have certainly suffered.

It illustrates what many of us know already, which is the incredible longevity of Kodachrome.

The mounts on both are embossed with the month and year, Jan '60.
No color adjustments in scanning or PS.