Here is a short list of what I think were the major mistakes made in socialist approaches to addressing poor distribution of wealth and other contradictions
Lack of spiritual engagement, denial that human experience must have a spiritual depth and therefore only reinforcing a materialist perspective, even while trying to redistribute wealth (thus assuming basic values of capitalism)
1) Emphasis on monetary value. Assuming value can be converted into cash, into numbers
2) Embrace of an industrial society and assumption that the organization of the industrailized society is the best
3) Lack of recognition for, and approval of, traditional ways of living and their wisdom.
4) Assuming the myth of modernity as an absolute break and a modern life is absolutely superior
5) Ignoring impact of industry or policy on the environment.
6) Ignoring the role of local government and of local village economies
7) Allowing for a centralization of the economic structures that made it easy for people to take over large units, privatize them and become billionaires overnight. The failure of socialism to build in guards against this abuse was a big mistake.
8) Lack of balance of powers between different parts of government to avoid concentration of power in one institution
9) Mistaken assumption that because markets are exploitative that there is no use for markets.