Managers’ interests can be aligned with the long term interests of the firm by giving them non-voting preferred shares as part of their compensation.

It really depends on the specific form of socialism. If we look at the most influential forms (say, USSR or China), the decision makers are politicians, so they’re more motivated by power and influence than the good of the whole.

IMO, socialism can work if it’s practiced by smaller orgs and not as a government structure. So unions and co-ops, not planned economies.