Taking a look at things from society's perspective, society decided that individuals should privately own for-profit businesses because, for a large subset of society's needs, that is the most efficient way to produce these needs. In that sense, capitalism as it exists is meant to serve society. It merely works out that the incentive to maximize profit in this system _approximately_ aligns with society's interest in acquiring goods at minimum cost---that is, if certain conditions, such as adequate competition, are met.

Of course this isn't the only reasonable perspective, but it certainly isn't false.