Your whole premise is wrong. Billionaires (equivalent, obscenely rich people) predate regulations. As a matter of fact, both initial regulations on business and socialism, communism, syndicalism directly came as a result and backlash of abuse of rich owners.

Also, you're under the naive assumption that lacking regulations, companies will want to compete. Why wouldn't they just form oligopolies/monopolies? Either due to natural restrictions (e.g. competing in infrastructure is way too expensive, usually), or the richest company/private equity buying up all the competitors to have a free hand at abusing the market.