Unwashed eggs are good for few months unrefrigerated which is lot longer than most foods. In EU, it's illegal to sell washed eggs and they're sold unrefrigerated.
Washed eggs without refrigeration expires in 1 day at warm temperatures. In USA, Canada and Japan, it's illegal to sell unwashed eggs and they're sold refrigerated.
This is likely why this Japanese author thought eggs expire quickly.
Eggs sold without grading aren't subject to regulations (like directly from farmer).
More countries in the world sell unwashed eggs than washed.
Washing eggs destroys the protective layer, "bloom" which causes the egg to expire. But unwashed eggs can have dirt, poop, feathers, etc on it. Despite being dirty, statistics show us the chance of salmonella poisoning is a lot lower (like 1/10th) in countries like UK who doesn't wash eggs than USA.
Further reading: https://www.npr.org/sections/thesalt/2014/09/11/336330502/why-the-u-s-chills-its-eggs-and-most-of-the-world-doesnt