thats because when u buy a console ur set for life, ther is no need to buy anutha one, so one or 2 per house hold, the sales will decrese as there is noo need for them to b bought by that house hold n e more,
but as a pc has to b updated all the time, the sales of them will always b the same. in all, they dont suk, they are just not as good as consoles