I think an organization like OSCOM has the potential to deliver great value and it is puzzling (at least on the surface) why a group of open source project leaders, who have proven their ability to lead collaborative initiatives, have failed to keep OSCOM on the rails.
I think that the problem is an uneven balance of effort and reward. In a good open source project, you get more than you give because every contribution that you make will be maintained and has the opportunity to be improved upon. Plus, it is likely that you needed to make the fix or add the feature for yourself anyway. OSCOM, on the other hand takes people away from the immediate things that they need to do to make a living. The rewards are too abstract and distant to affect an immediate decision of what to do with your time.
OSCOM is all about the greater good and provides very little immediate personal good. A less influential open source project might invest time in OSCOM to get exposure and establish a name for itself. But the larger projects have their own communities to worry about and are less concerned with open source content management in the abstract.
So, if the OSCOM concept is flawed (I don't know this for sure, but lets say it is for sake of argument) what are alternative ways to deliver the benefits of promotion of standards, collaborative innovation across projects, and promotion of the open source alternative? Here are some ideas.
Submit standards to existing standards bodies. For example there was a lot of open source input into the JCR standard.
Attend each others conferences. By attending another project's conference, an open source developer can get new ideas and also build professional relationships with other developers that he can potentially collaborate with on shared components.
Establish joint projects for share components.
The other constituency that also loses with the collapse of OSCOM are the users who were not really contributing but would have benefited from a centralized place to learn about open source content management software. The CM Matrix, which never really lived up to its full potential, was a valuable resource but not quite as good as CMS Matrix or Open Source CMS. Planet OSCOM that aggregated a bunch of open source developer blogs does not seem to work any more. Perhaps, that could be moved over to CMS-News or some good del.icio.us tagging.