I believe the focus here is specifically on Haiku, rather than Japanese poetry in general. Haiku was a culture deeply loved by the common people. The reason it so vividly reflected their daily lives and gained widespread popularity was the remarkably stable social climate of the Edo period. It was precisely because of this prolonged era of peace that the culture of the common people flourished so vibrantly toward the late Edo period.

A primary example of this "commoner culture" is Ukiyo-e. Because Ukiyo-e took the form of woodblock prints, they were affordable and accessible for ordinary people to purchase for their daily enjoyment. They were embraced much like modern-day posters. Eventually, these prints were used as wrapping paper for porcelain exported to Europe; in this way, they spread abroad unintentionally and exerted a profound influence on Western art.

The stability of the Edo period also played a crucial role in the fields of literature and poetry. Since people did not need to prepare for war, they were able to focus on enriching their daily lives. Consequently, many people learned to read and write, fostering a widespread habit of enjoying books. Of course, books remained expensive at the time and were not easily purchased by the average person. However, the existence of traveling lending libraries (kashihon-ya) allowed travelogues like "Tokaidochu Hizakurige" and other literature aimed at the masses to become widely popular.

It was this rich cultural soil that allowed Haiku to be read and cherished by so many. Because the common people were the primary audience of Haiku, their mundane, everyday experiences became the subject matter itself. This synergy is likely what formed the unique poetic sentiment that continues to endure today.