Regarding how advanced production needs to be for social planning, it must not be an impedement for production. Essentially, by the point that decentralized production has transitioned to monopoly, markets have played their role. That's why in a socialist country like China, the commanding heights are socially owned, while for developing industries these are privately owned to a large degree. At the monopoly level, privatization impedes progress.
As for your bit on political parties, you're continuing to argue against a caricature you invented in your head. Nobody has stated that elections must be controlled or exclusively of party membership. You have to argue against a strawman, because your point collapses when confronted with reality.
Please be serious.