Thing is, studios will use tools like Maya if they meet their needs, and if not they develop internal proprietary software that does exactly what they need. Often they use both in different parts of the pipeline. It is not obvious that there is a space for a third option there of collaborating to build a complete end to end 3d application that will inevitably require compromises.

Open source already happens with specific focused packages (OpenSubdiv, OpenVDB, PTEX etc) which can be very good at one thing. Developing a complete 3d application that meets everyone's needs is unlikely to be appealing given the diverse studio pipelines and requirements.