For me, CLA and DCO have different purposes and are not the same documents.
If I totally agree that government should never propose CLA, I am more doubtful regarding organizations that would be responsible for the code, once the project is mature enough to be part of an organization.
The questions is for me the most probable risk occurrence:
- What is the risk that code needs to be relicensed? I have the Wikimedia history in mind with the migration from GFDL to CC-BY-SA
- What is the risk of the organization in charge of the project closing future development of the software?
Also from an impact perspective, isn't the impossibility to adapt the license more harmful than the possibility to fork if future development were closed?
Last, isn't setting up a CLA a best practice of good IP management? What is the history and reasons for Apache and eclipse CLA for example?