What you are saying is generally true in practice, but not an absolute feature of labor agreements. In the simplest case, two people working together can create more value/profit than each working individually.
A genius programmer and a genius game designer will do better together than apart, and there are a lot of reasons why they might organize so that one owns the business and the other takes a paycheck. Add in a graphic artist, an audio engineer, etc, and they are probably not all interested in becoming part of the business.
On the other side of the scale are publicly owned corporation where holding stock has nothing to do with generating value or profits. That is the heart of what makes capitalism capitalism, when the possession of sufficient capital produces leverage over workers and inherently unfair compensation.