Why did Japan lose its economic momentum after becoming one of the world’s most successful economies?

Japan went from a war-torn country to one of the world’s largest and most advanced economies within just a few decades. By the 1980s, Japanese companies dominated industries like automobiles, electronics, cameras, and consumer technology, and there was even widespread concern that Japan might overtake the United States economically.

Then the momentum largely disappeared.

Japan has remained a wealthy country with many globally successful companies and a highly developed industrial base, but its economy has grown much more slowly since the early 1990s.

What changed? Was it mainly the asset bubble and its aftermath, demographics, declining productivity, changes in global competition, or something deeper about Japan’s economic model?