The industry practice is

that a major developer or GC will typically work with a "principal Professional" for their design service. Typically, if the projects are commercial in nature(for example, homes, schools, churches, shopping centers, stadiums,etc), the Principal Professional would be an Architect, the architect will hire his structural, MEP consultants. Geotechnical is normally work for structural. If the project is industrial in nature (for example, power plants, chemical plants, oil and gas facilitiues, etc), the Principal Professional would be a PE, either Mechanical or Process Engineer, then he will have discipline engineers under him, such as Civil Structural Architect, Mechanical,Electrical and I&C.

It is rare that a developer or general contractor directly work with a geotechnical engineer, because he has to coordinate the interface between geotechnical engineer and the structural engineer, they would rather focus on planning or construction.

If you want to have your own business someday, maybe you should develop more relationship with structural engineers, because majority of your potential clients are structural engineers.