Fair-code is not a software license. It describes a software model where software:
- is generally free to use and can be distributed by anybody
- has its source code openly available
- can be extended by anybody in public and private communities
- is commercially restricted by its authors
Without every single contributor assigning copyright to a single entity for their code, the only way to commercialize a program distributed under such a license is to get every single contributor to agree to it separately (or not use their code).
If every single contributor assigns copyright to a single entity, the project is now controlled by it, and unless that entity was particularly nice with its contracts, those contributors are now powerless if (for example) this entity decides to change the license.