I think that social and income inequality in Japan will never be eliminated near future.
In this age of globalization,world's resources are diminishing and its population is growing rapidly,which would lead to catastrophic consequences such as starvation and conflicts.Also,disparity between poor and rich is growing consistently due to globalization.However,Japanese government promotes globalization and encourages the japanese companies to complete with rivals which have headquarters in other countries.
As for inequality between younger and elderly in Japan , a consequence of an aging population means that young workers have to carry the heaviest economic responsibility,but they would receive less pensions and medical care than the elderly.Furthermore,they may be forced to work unreasonable hours to grow productivity due to a decline in the working-age population.
Last,thanks to technological developments,it is theoretically possible that starvation can be eliminated.However,this does not mean that income and social inequality will disappear.some articles and experts said that our incomes tend to depend on which university you will graduate from ,but tuition and entrance fee are increasing consistently.
When considering the points mentioned above,it is unrealistic to expect that social and income inequality will be eliminated.