Free enterprise cannot exist when a government owns all businesses, but it also cannot exist when one or more companies control the government.
The heart and soul of free enterprise is competition. And we have witnessed how well this works when huge corporations like AT&T and IBM were forced to divest much of their growing monopolies over their respective segments of the U.S. economy. Growth of competition was spurred which caused massive reductions in the cost of computing power and telecommunications as well as remarkable innovations in both of those areas.
Just as competitive sporting events require rules, referees and umpires, competitition in business also requires regulation and oversight. That is the role of government. And it makes no more sense for businesses to control politicians than it makes for a team to control the referees or umpires. When one or more companies exert too much influence on a presumably capitalist government, that government becomes indistinguishable from a communist government.
It is remarkable that some people express great fear of government growing too large but fail to recognize the dangers inherent in corporations growing too large. Such growth tends to place a company out of touch with the consumer and stifles innovation.