[jedi_master]

What was the purpose of bell labs making unix or linus torvalds linux? Why is apache free? open source C compilers? python, java, mysql, go-lang, rust, angular the list goes on.

Open technology helps evolve the type of applications we can build. There doesn't have to be a "play". Facebook made something good that makes their lives easier and their product better. By open sourcing or sharing react whichever it is they allow other people to contribute which in part makes their product better but also increases the quality or reduces development time of the applications that anyone else using it builds.