No. Manga has roots further back than the twentieth century.
It came from the Tokugawa Shogunate during the 17/18th centuries. The Shogunate was able to maintain peace for over 2 centuries and as a result, a money-based economy developed. (before, all currency was based on Rice Crop). The population increased, and cities were getting bigger and bigger.
Farmers still farmed, but now that they had a disposable income and more time to work with, the came to be a demand for entertainment.
Thus, the manga industry began. Within these cities, Artists and writers supported themselves, no longer by farming, but rather by writing comics and such.