Anybody ever heard of the term "console seller". Yeah, that's why exclusives ARE important. And yes, KLAMarine is right...that, of course, implies they are great games and people are urging to play them.
Only having exclusives for the sake of having exclusives, mediocre ones and especially timed, rarely works out, as we all know. That's why dedication and variety are so important and that's why Sony and Nintendo are so successful.