What's the point of that wasted effort? What you're asking is "if X has no contributors, why don't Y people become contributors and start contributing?"
Currently there are differences between code bases. If the OpenOffice team wants to abandon OO codebase and distribute a version of LibreOffice with some splash screen and text resource changes, then they're free to do so, it's open source.
I was thinking more like a takeover of the Open Office codebase since its organization has collapsed. Take over the administration, steering committee, etc.
I can see that the codebases have diverged, but will a lot be lost if Open Office's codebase was clobbered with the LibreOffice sources?
Currently there are differences between code bases. If the OpenOffice team wants to abandon OO codebase and distribute a version of LibreOffice with some splash screen and text resource changes, then they're free to do so, it's open source.