One of the things I consider most strange about commercially-tied open source projects is the lack of co-opetition.
Why do we need separate Apache projects for Axis2 and CXF?
Well that's because IBM and WSO2 'run' Axis2 while CXF is backed by Progress Software.
Why do we need OpenJPA? Why not just storm (I mean collaborate within) the EclipseLink project?
Its amazing to me how many open source projects have only a single company's backing. What happens when that company deinvests? I think organizations like Apache and the Eclipse Foundation work hard to get these players to see the light and work hand-in-hand on a common code base (for the good of the community), but I guess its somewhat against the open source ethos of letting "a thousand flowers bloom".
Maybe it has something to do with whether the companies involved are market leaders or not. Second and third tier companies have the most incentive to collaborate. If you're not the market leader, its in your best interest to band together to 'defeat' (or at least compete with) a common enemy. And open source is the perfect place to do that.