I disagree that most Japanese are Buddhist rather than Shintoist, having lived in Japan for many years, and being a fluent speaker of Japanese. While some people maybe ardent Buddhists, or ardent Shintoists, the majority to whom religion is a thing reserved for special occasions use shinto for some things and buddhism for others. For example funeral rites tend to be buddhist, whereas celebrating the birth of a child, the parents would take the baby to a Shinto shrine. People see the old year out at a buddhist temple, then in the first few days of the new year go to a Shinto shrine. Shinto tends to be associated with birth and life, Buddhism with death.