So our heroes don't solve the problem and V'Ger fries Earth.
V'Ger itself is screwed because it never can find its Creator and have nowhere else to go.
What about of the rest of the Federation? Earth is gone. Are the Vulcans, Andorians and Telarites madly scrambling or meh? The enemies, Klingons and Romulans, did they threw a party or are afraid of V'Ger?
Then the Whale Probe comes for its friends and finds the planet scorched and V'Ger still thinking about what to do with itself -- or not.