First, they do often fail and are replaced by new companies where sclerosis hasn't set in yet.
Second, even huge megacorps are tiny compared to countries. Microsoft is about the same population as Antigua and Barbuda, and if Antigua and Barbuda tried to go the Soviet state controlled economy route I predict that they would be much more successful at it than the Soviets were because its much easier to govern a smaller country.
Comments
First, they do often fail and are replaced by new companies where sclerosis hasn't set in yet.
Second, even huge megacorps are tiny compared to countries. Microsoft is about the same population as Antigua and Barbuda, and if Antigua and Barbuda tried to go the Soviet state controlled economy route I predict that they would be much more successful at it than the Soviets were because its much easier to govern a smaller country.