Google should open-source the project and let the community take over and continue development.
As Steve Yegge always points out when he talks about open sourcing his Google side projects, Most of it depends on other Google technology that isn't open source.
That doesn't really prevent you from open-sourcing it. The Google-specific parts can be replaced by someone who cares.
> They probably can't in any way that would make it usable to people.
No worries:)