Because the internet says so.

now I have to believe

Take it from someone who actually lives here (japan), there is constant talk of PS4, not a single place offering ps4 preorders had any left within 12 hours of going live the second time, within 30 minuted the first time, I'm constantly seeing kids in the street talking about it, hearing coworkers I talk to in bars talk about it.

Not sure why you feel Japanese are some sort of unknown species that don't find games westerners play as 'fun' cannot count the number if times I've heard talk of knack, killzone and the order.

But hey, what would a Japanese person living in japan know about japan over someone who doesn't?

Common sense... Baring a Ps3 price drop within the next year it will recieve less sales than it did last year. (Kowenicki swears to a 30% reduction... which would be less than 8 million.) Ps4 willsell more than 1/4th of eight million on its launch weeks aligned

even Gamespot said Wii U was almost sold out only with pre-orders. And common, it's not common sense. You are a PS fan, I am too. I love my PS3. But just because you want something doesn't mean it will be real.

Gamestop saying that doesn't change the fact that in first week sales the Ps4 will have over 2 million sales. That would only leave 6mil remaining in the other weeks

Skepticism is just as inaccurate as optimism, just saying.

some people here said that some Wii U predictions are delusional, but what about yours? Do you really believe that? I just want to know

the ps3 did 7.9mill it's first year (2007) the ps4 is coming with more hype, cheaper and with a weaker competition worst case the ps4 does around 8mill first year. Now ask yourself this do you really see the PS3 selling more than 8mill in 2014????

The Wii U didn't have over a million in preorders months before it launched.  Wii U had 500k at Gamestop the biggest gaming chain. Since Sony announced over a million pre-orders they have said they will produce more than that for people who havent preordered AND they have taken more preorders AND started accepting preorders in places like Japan. Ps4 will no doubt sell damn close to 2million first weeks aligned. Ps3 has been declining for a couple years now and will probably suffer its biggest yearly declines next year due to the new consoles. Of course I believe the Ps4 will outsell it.