Why do private sectors typically end?

Private sectors of a nation's economy, for the most part are increasing. This is due to the failures of Government owned enterprises. Russia and even China are moving more towards creating private sector aspects to their economies.

On the other hand, at times private sector industries fail and go bankrupt. This is usually a short term situation, and as in the case of General Motors, the US Federal Government became a major stock holder of the new GM. This was a temporary situation.