How Does Chinese Communist Party's Propaganda Evolve with Time 現實比小說更離奇

In 1985, the slogan says: "Family planning is good. The government will provide for the elderly."
In 1995, the slogan says:"Family planning is good. The government will help you to provide for the elderly."
In 2005, the slogan says:"One should not rely on the government to provide for the alertly."
In 2012, the slogan says:"It is good to postpone one's retirement; so that one can provide for himself or herself."
In 2018, the slogan says: "It is everyone's duty to provide for elderly in one's family, and it is shameful to push this responsibility to the government."