"Free" doesn't mean unregulated free-for-all, it specifically means that people are free to enter the market as buyers or sellers, and free to choose what and when to exchange, at what price. The government does not regulate who is allowed in the market, nor the prices; but rather would get involved by protecting those freedoms to engage & price.

Monopolies work against a free market, as do barriers to entry. Businesses make more money if the market is not free, i.e. if others in the market are not free to choose competitors' products or to become a competitor themselves. The "invisible hand" is about reflecting pricing movement of free exchange, not enforcing the freedoms. If a society wants a free market, they need to set up rules that promote market freedom as a societal goal, which would (ideally) end up working against individual profit maximization (compared to a usurpable market) but for greater overall robustness and correction.