Sales numbers make fanboys cry, so they get around the problem by pretending they don't care about sales - it's about the games, stupid. Which, coincidentally, is a good attitude to have. After all, they're just consumer products and the games they like will indeed still be made.
You'll note though, that this thread's view to post ratio shows that they in fact,
do care, but they're just not posting out of fear of embarrassment or having their previous triumphant prediction posts rubbed in their faces. Only the bravest
fanboys dare to come in here spinning the numbers now.
There are a few who secretly or not-so-secretly hold out hope that one game will come along and turn things around, in spite of all the evidence and past experience to the contrary. Many of them used to sport FFXIII, Killzone or MGS4 avatars and are currently wearing the LBP warpaint. They're silently waiting for the numbers to come in that will vindicate them, so that they can make their triumphant return, but will remain silent if the numbers are not in their favour.
Which won't stop the spinning and meltdowns by the crazier fanboys, of course.