Before V'GER/Ilya merges with Decker, Spock suggests that VGER has reached the limit of knowledge and thus, must evolve to some higher purpose...if VGER only went to some other place in our galaxy, and then came back to Earth, how could it have possibly emassed 'universal' knowledge considering how big the known universe is....Is our galaxy THAT important that everything to be learned from traveling around it for 200 or so years? Seems kind of 'arrogant' to suggest that.
Well, it was only Kirk, whose information was thirdhand, who said that V'ger had travelled to the other end of the galaxy. Spock, when he was actually travelling through V'ger's databanks and observing their contents, said that V'ger had knowledge spanning the entire universe, and the images he beheld certainly seemed to encompass multiple galaxies. So I consider Spock's assessment more reliable than Kirk's.
In my TMP sequel novel
Ex Machina, I established that V'ger had actually been flung back in time as well as across intergalactic space, and had actually spent millennia searching the galaxies for its Creator and evolving into the Maui-sized living cybernetic entity it became.
What one of our famous authors on this website needs to do (Ahem..Greg and the other) is write us a sequel...where did VGR go AFTER the Motion Picture...
I also addressed that in
Ex Machina.