And think about all the merge conflicts you have to resolve after 3 months of code changes.
It's always noise to people that don't care, but matters to people who rely on AOSP, including third-party ROM developers.
As others say, it breaks contributions and any chance that other forks will keep up.
Lol nice pipe dream. The source isn't even fully released today.
The obligation is specifically to provide the source code (without certain usage restrictions) for binary releases when requested, and no more.
Note that the demand for secrecy is primarily driven by device manufacturers, not Google. Manufacturers want to keep their "secret sauce" from their competitors.