There's a reason I point out the longevity of OpenStack. As a project, it has significant corporate sponsorship and policies to ensure that one entity can't take over control of it. For instance; the OpenStack Technical Committee is never permitted to have a majority membership made up of a single entity's employees. This means that even though Red Hat, at this stage in it's development, has a majority of contribution, the project itself can never be taken over by a single entity.

People find project governance, and particularly "corporate" involvement in open source to be distasteful -- but in my experience, and OpenStack is a winning example of this -- setting up good boundaries to let companies work together has proven to be sustainable.