Dekotora: The kitschy world of Japan's pimped up trucks
https://edition.cnn.com/style/article/dekotora-japanese-trucks-subculture/index.html
I guess the reason why truck decoration became popular is hard work and high salary.
More than 20 years ago, truck drivers were famous as better salary and tough work.
It means they have no time to spend money while they earn a lot. So, the only way to spend money is to invest their tools on duty. Then, decoration of the trucks would be one of the potential candidates.
