GPLv2§2(a) does not say what you think it says

I can comply with your interpretation by supplying at tarball that contains a git repo with a single commit -- The complete corresponding source code to the binary I'm distributing. I am under no obligation to supply the source code to binaries I did not distribute, nor am I under any obligation to distribute any/all prior versions of the source code. [1] [2]

...Or are you arguing that everyone should be forced to publish every private intermediate draft or edit, even if there was no external distribution of anything (binaries or source)? Is git squashing and rebasing now verboten?

[1] I make a minor change to Linux to support my hardware. Should I also have to distribute all 3GB of Linux's upstream git history? What about upstream's pre-git history all the way back to 1991? If the answer is different, why,? What's the cutoff? one version? Five versions? One year of history? five years of history? What if I don't use *your* preferred VCS at all? Can I comply by supplying a SoS, Perforce, or Bitkeeper repository (that you may not be able to legally access because you worked on a competing VCS in violation of the Bitkeeper license)?
[2] Overly pedantic folks can argue that one needs to include "prominent notices" saying the date of your modifications (GPLv3 5(a) ) -- But you don't have to enumerate your specific changes, and the "date" can just be when you publicly published them in the modified work. Still, you can achieve both by your tarball'd git repo having two commits; the first being the unmodified upstream source code, and the second containing all of your changes.