No, growth coaching works for both startups and mature businesses and corporations. Moreover, the larger the company, the greater the effect of working with a growth coach.
The goal of a growth coach is to help you focus your efforts on what will lead to results the fastest.
The bigger the business, the more efforts you can focus on, the bigger the results you strive for, and the greater the effect that your resources will not be wasted on those tasks that do not lead to growth.