It is not comparable at all, first of all walmart handles only one specific field, unlike the state having monopoly on everything. Second, there are competitors

It is not comparable at all, first of all walmart handles only one specific field, unlike the state having monopoly on everything. Second, there are competitors to walmart so when walmart starts to do crappy job a competitor that does better job will drive it out of business. Third if you build your own robot walmart won't be able to take it, and socialist state will have to take it to remain socialist. All of this forces walmart to listen to the people who consume its services, in socialist economy no one has incentive to care.