because many are controlled by their feelings and hopes.
i would not even predict something after minimum the second holiday season. ps4 could sell much better as xbox one because they have obviously many more fans who go with the company since ps1 and will buy the console the first weeks after launch but that wouldn't mean that xbox couldn't sell much better in the second or third year if people would start to like what xbox will have to offer (which can also change drastically after the years)
and people should still not believe that nintendo already lost. it will be hard for them but if they will have a successful relaunch (i think they will do something like that) they could still be very successful.
or microsoft will have a crazy start because the mass market will love xbox one even for a high price and after a year they will all lose the interest. who knows...
probably the reason why i never really make predictions on vgchartz, video game market is just too unpredictable to make serious predictions. all the predictions of the analysts before this gen are a good example. they all failed hard.
