The highly regulated, protectionist Japanese economy, and an overall collectivist culture, leaves little room for flexibility in executive pay. This makes Japanese businesses less competitive, and work life more miserable.
Economic growth results from increasing production, and the money supply is always sufficient to foster exchange. The boom-bust cycle only occurs when production is distorted by a growing money supply.
Proponents of modern monetary theory have come up with their own idiosyncratic definition of savings in support of their theory. But the common usage of the term shows MMT doesn't work the way its supporters think it does.