Monopolistic markets often react faster as a result of knowing the consumer better. Times are changing rapidly and so adaptation is key.

Oligopolies are in fact good for the government considering they provide better government oversight. Increases accountability and can be sued in court, take legislative action.

Oligopolies are more resistant to economic downturns due to their prominence; thus they can be considered more stable. Consumers are always covered no matter the economic climate

Monopolistic markets provide more options of choice and are often more inclined to provide better services to their consumer. The oligopoly on the other hand is prone to become stagnant in terms of research and development

Free/Mixed Economies introduce many new markets at a faster rate as a result of supplying various needs. Often times new markets means more growth as seen in the cases of creating the stock market. Even in cases that seem trivial like selfie sticks etc. New markets means more goods produces, which requires more labor, which requires wage, which increases purchasing power.

Free/Mixed economies make it so that private citizens are more informed of the wants of other citizens, thus, can better serve to their needs with goods. Benefits to all parties come from this point. Private producer gains cash (Raises purchasing power that can be reinvested), consumer derives enjoyment from good.

Stimulates a fledgling economy to the point where basic goods and industries can be established. Planned economy can function as a 'jump start' for a nation's economic growth, introducing it into the global market quicker. Reason planned economy has this effect is due to the fact that governments usually have more/better capital (clout) than private citizens and can more easily use it.