But without Socialism/Communism there would be no government subsidizes and the market would be free.
Oligarchy is dependent on Socialism. In a socialism the state takes control over the market and that is how U create Oligarchy.
Due to a natural phenomenon such as synergy, every attempt to control the market will result in a further merge between the market and the state. Until there are no free market and a handful oligarchs are in near full control.
No Socialism, no Oligarchy