It's not "It's like one month of great sales", it's based on history, price and market analysis. I have explained in detail, if you bother to read it. But of course, you seem to be on the other camp, so I don't think you'll be willing to go through all that pain. But as a quick summary,
PS4 will definitely do better than a LATE, EXPENSIVE, DEVELOPER UNFRIENDLY CONSOLE, WITH BAD MEDIA COVERAGE. Anyway you may wanna spin it, the history tells us that it will sell past 100+ million. However, that's not just it. There is no mighty Wii this generation. Also the Xbox is doing a lot worse everywhere, and as of now, there is not one single country it is leading, not even in US. This is not just a coincidence, but evident from the huge demand for PS4. Also just take a look at the history to learn that the more expensive console never has a chance in US. So forget about an Xbox victory in US, never gonna happen. All that brings PS4 sales estimates way past 100+, easily surpassing PS1, and closing to the PS2.
Another thing people forget is that PS2 sold 140 million in around 5 years. PS4 has 7 years to catch up. So it doesn't have to sell that fast. Also the market is larger now, making its job way easier. So PS2 levels of SALES NUMBER is within reach. However, that kind of MARKET SHARE is a tough DREAM.
I read your post it's one thing I always try to do before responding. The problem was it was ignoring NEW trends. This isn't 1999 or 2006 where there was less people taking over the gaming section. Let me break this down by responding to your points.
"PS4 will definitely do better than a LATE, EXPENSIVE, DEVELOPER UNFRIENDLY CONSOLE, WITH BAD MEDIA COVERAGE. Anyway you may wanna spin it, the history tells us that it will sell past 100+ million. However, that's not just it. There is no mighty Wii this generation."
Again this based on a market that didn't take 8 years to get a "hardcore system" to 80 million. PS2 was able to do it in 5 and had the causal pull with the DVD player. Like it or not traditional consoles have taken a big hit. Grouping wii sales with ps3 and Xbox 360 is not a good way to judge a market for ps4. Why? The reason being is the people who bought the wii are not same as the ones who bought a ps3/xbox360. They didn't disappear from wii base they MOVED on to tablets and iPhones. Please tell me how ps4 is going draw in grandma and grandpa? It's not. Tell me how it's going to get the iPhone (casual market)? It's not. Fun fact more kids are starting to play there first games on smartphones than on consoles.
Side note: Japan sold 20+ million ps2 in just Japan. Looking at the market now, it would be lucky to get a 1/4 of that number.
"Also the Xbox is doing a lot worse everywhere, and as of now, there is not one single country it is leading, not even in US. This is not just a coincidence, but evident from the huge demand for PS4. Also just take a look at the history to learn that the more expensive console never has a chance in US."
Correlation does not imply causation.
Just because one system is failing doesn't necessary mean one is going to get that audience.
Example. PSP sold 80 million but Psvita is underperforming. Therefor 3ds should be getting that audience. Guess what? That isn't happening. You know why? Because the market doesn't work that way.
The wii got its giant instant fanbase NOT because ps3 was failing but because it's was getting a new audience. Using your argument Xbox 360 should be the real winner being at 160 million. Why is that not the case? Because the people who bought it for more reasons than gaming or other reasoning. I would argue the fanbase of Xbox or ps3 are exactly directly related. Example, many people bought a Xbox for media reasons.
"So forget about an Xbox victory in US, never gonna happen. All that brings PS4 sales estimates way past 100+, easily surpassing PS1, and closing to the PS2."
This called jumping to conclusions. The Xbox/Wii U could be gone tomorrow it still wouldn't mean in this current market that ps4 would sale that amount. You are making a one-dimsional argument that the console that was priced the highest never sold the most in US. This isn't even factually true. The GameCube was priced lower than ps2 at 200 dollars. I don't believe you even did any factual research on some of your own revisionist history. Ps2 was priced higher because of its DVD player in it. You also Therefor, not only is your logic fallicous but even it's arguments are counterfactual.
Most of your arguments assume everything will react like it did in 2000 or 2006. I can't see how you can rationally tell me the market didn't change seen that time period. It's like you think everything works in super-linear way. If x happened in 2000/2005 than it must worked in 2014. It's like we should ignore other technology because consoles are the only thing that will never be effected by anything else. To put it simply, it's like you think the consoles are in some magical bubble that will grow forever and nothing can hurt it. My point is markets are never that narrow and simple. If you want to creditable even a prediction you should take into account many factors and check what the facts really are saying.
"Excuse me sir, I see you have a weapon. Why don't you put it down and let's settle this like gentlemen" ~ max