Robin Hood Designers take some percentage of the income from their commercial projects and invest it into really sustainable projects. That means they devote xx percent of their time and creativity to real sustainable products. After they have done that for a while, they will be known for doing these sustainable projects and get more experience, as well as more reputation and skills. Then companies and other organizations will hire them especially for these skills. Thus they can do MAINLY sustainable projects.
The initial obstacles for getting into the movement of running sustainability design projects gets reduced. After a while sustainability design will become the USP of the designer/ the design studio.