How do you have a planned economy with a democracy and elections? You believe people are capable of making decisions as to what it takes to run each and every business, or even if they only vote to pick one person to run one company, you think they can know the person's qualifications, how well they will fit into the company, and be able to evaluate their ongoing performance?
Even better, you think people will actually take the time to study these things before voting, instead of turning the entire planned economy into a popularity contest?
1. I mean USSR had only single party, so it led to elite's degradation. If we will allow multiparty system with political competition this won't happen (banning only pro-capitalist parties the same way as nationalist/far-right parties banned in Germany now).
2. As I said later, state-wide ERP software can help to measure performance.
3. I think it is reasonable to require passing some qualification exam for the people who want to participate in the voting. People will have a lot of time thanks to automation, so why not to learn!