Don't think GT6 is the best example since it release during a generation transition.Well GT5 sold like over 10 million to GT6's 2+. Maybe people are finally getting fed up with shitty sounds and PS2 cars and tracks on PS3/4. GT7 has a lot more to prove than FM6. If you hang around GTPlanet you'll find a lot of people who are looking elsewhere for their simracing fix, be that Forza, PCars, AC and other PC sims.
Yes it can be important, but that still doesn't warrant listing it with exclusives. Destiny still sold a ton on Xbox.
Definitely.