Japanese corporate governance does not work quite like in the US, either legally or culturally. Shareholders actually generally have more decision making power than in the US but tend not to exercise it very often and basically trust the existing leadership.

Toyota has been publicly traded for 70 years and their shareholders (which are primarily other large Japanese conglomerates) have never even tried to make these kinds of short-term-over-long-term pushes and keep electing Toyoda family members into the top leadership positions.