There aren't any $15/hour jobs in my company. There are three principal owners/designers/managers, including myself, two project managers who also do a lot of the CAD work and a contract CAD guy. There is one owner who is the bean counter and paid similar to the other owners and there are support people that make less, but they make a lot more than $15/hour. We are not a contractor. We design systems, specify/design/buy and sell custom equipment and standard equipment, manage installation and commissioning and do audits and studies looking for cost savings through reduced energy usage or improved productivity with existing systems.
I understand that an electrical contractor will have lots of lower paid people on his payroll but I would expect a contractor that does many large industrial projects to also have several electrical engineers who can provide all the necessary design services for a large project and could, when needed, provide the higher level on site technical service that is sometimes, but not always, required. In fact, we have worked with electrical contractors who have those capabilities. Many of the projects we are involved in do not have an independent electrical engineering consultant. The electrical contractor does the necessary design, provides the drawing required for permitting and installaton, and manages that side of the project. We provide them with the electrical requirements for the equipment being installed and they take it from there. It's really pretty common.
Our profit margins are fine. In fact, we're growing quite fast at the moment due to a shift in the market that is giving us new opportunities.