That's probably more true outside Japan than inside it. By then, just to mention one factor, Miyazaki and Takahata had already smashed the Japanese box office multiple times with "militant" environmentalist films like Nausicaa and PomPoko. In fact, I remember the whole environmental theme being a bit of a clichè in my part of the world (Western Europe) by the late '90s - for us, those themes had really exploded in the '80s as part of the debate over nuclear energy.