There are two factors necessary for a truly free market that prevent any capitalist system from actually being a free market. They are:

1. Consumers need to have perfect information about the products and the companies that make and/or sell them.

2. There needs to be zero friction for new entrants into the marketplace, whether that is from costs to start up a business, or anti-competitive behavior from other companies with money to throw around.

It is impossible to achieve either of these in the real world.