What's more, as we all know, Japan's territory is very small, so housing prices in Japan are very expensive. Most Japanese people live in a narrow space. Cats are small and flexible. In addition, cats love to be clean, so it is more convenient to clean up. Having a cat won't make the house look messy.
Finally, I think the Japanese love for cats is related to their feelings for Lori. Japanese people like cute and weak creatures, which can be seen from their popular actresses and comic themes. Cats are like cute and soft little girls. To sum up, so many Japanese people like to keep cats.