By moving the locus of control, whether it be considered the ceo or shareholders, so far from the actual business and implementing mandates based on whatever the current fancy is and meaningless targets of growth on such a giant scale you get the same sort of excesses.
The current system is marked by irrationality and uninformed and ill considered decision making. With smaller organizations and actual business competition they would be held to account by their competitors or just by running out of money before something catastrophic for the greater economy happened.
Large monopolistic mega-corporations do tend to have the same issues that one would see in the old 20th century planned economies like the Soviet Union.
It is much easier to exit from or steer a private org. For example, it is very possible to run a company which caters to 10 percent of a consumer base by providing niche products which may be slightly more expensive. Those 10 percent will simply consume less of some other good. It is very difficult to do an analogous thing at the state level, because we generally don't get individual "ticket books" which we can "spend" on more of one state service vs. another. The democratic model is that you first get 50+ percent support and then your coalition decides how resources are allocated for almost everyone.
In some metrics (such as GDP), yes. And in other metrics (such as wealth inequality and health care), the answer is less clear-cut.