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.

Actually, the ps2 sold about 100 million in its first 5 years.

PlayStation 2 sales figures (production shipments) (based on official financial reports[1][2])
Date Total sales (cumulative)
Fiscal year ending March 31, 2000 1.41 1.41
Fiscal year ending March 31, 2001 9.20 10.61
Fiscal year ending March 31, 2002 18.07 28.68
Fiscal year ending March 31, 2003 22.52 51.20
Fiscal year ending March 31, 2004 20.10 71.30
Fiscal year ending March 31, 2005 16.17 87.47
Fiscal year ending March 31, 2006 16.22 103.69
Fiscal year ending March 31, 2007 14.20 117.89
Fiscal year ending March 31, 2008 13.70 131.6
Fiscal year ending March 31, 2009 7.90 139.5
Fiscal year ending March 31, 2010 7.30 146.8
Fiscal year ending March 31, 2011 6.40 153.2

I think your prediction fine and all that, but giving already market shares to each console and saying that those are very accurate is pretty non sense imo. I mean, they might seem logical as of now, but it could all change if something drastic happens:

Here some possible game changers:

X1 or WiiU make a drastic pricecut.
Some one releases ANYTHING that wins back the casuals that bought the Wii.
Xbone buys a HUGE developer/franchise/publisher, etc.
A 4th big player enters the market, with a more powerful console than PS4 (Google, Samsung, Apple)
PC becomes bigger and steals a big chunk of the traditional players from the console market.
Something else...

I mean, there is so much that could happen, I think predictions are fine, but to say they will be accurate is waaay to early for that.

Some confusion on my part, but even better for ps4 then, because it's easier to beat 100 million in 7 years (or whenever the next ps is released). In short, PS4 is likely to have sold better than any of its predecessors when its successor is released.

In plain English, it's likely that ps4 will have sold more consoles when ps5 is released than ps2 had sold when ps3 was released.

I see PS4 definetly selling 100m up until next gen arrives, and another 20 million or so alongside the PS5.

Your estimates are very silly. Xbone can go up to 75m? PS4 up to 165m? 25-50m range for the WiiU?? Very laughable. PS4 wont outdo PS2. The Xbone will lose marketshare in the US and UK, it cannot do anything close to 70m. 360 will end up selling around 90m, I expect the Xbone to lose around half of the marketshare.

WiiU 25m minimum? Lol more like 15m is gonna be it's maximum, it's selling ~3m a year.

Even with all the controversy around your numbers, I have to congratulate you by doing your estimations with a solid method and detailing the decisions you made in the process.

I agree that the difference between PS4 and One will widen. Right now, we only saw early adopters, that are pretty much price insensitive consumers, buying units. When these guys are done, and it's happening now, we will see the mass market that cares about pricing.

About your considerations of market size, I agree with you, market won't shrink. It would even throw if it wasn't by all casuals Wii got in 2008-2010 and lost to mobile. We saw the two biggest launches in history and that was for consoles way more expensive than the normal 300 dolars gold spot. Besides that, consoles are more mainstream now and emergent markets like the BRIC countries, that were always lagging behind in console adoption, now will be at full force buying these new devices.

There is a bit of a misunderstanding here. You don't seem to have read it detail but let me a bit more clear here...

First Xbox... XB1 will definitely lose market share (from 50% to a 24-33% share among HD consoles), I agree. However, the HD Consoles overall will gain market share against the Wii console from 60% to the 80-90% range. Assuming that the market size stays constant (which I doubt), the given range is what MATH tells me. The variation between 47.5 to 73.3 million is there because of those two ranges (80-90% for HD, 24-33% for XB1).

Basically the same story for PS4. Now think about it to meaningfully compare it with the PS2 era.

- XB1's competition is much more fierce than the competition from original Xbox but it's comparable to the Xbox & Gamecube combined.

- The market is much larger than the PS2 era.

- We are talking about a 7 year run. PS2 had sold 100 million when PS3 was released. 50+ sales happened after drastic price cuts. Assuming PS5 won't be released before 2020, PS4 has plenty of time to catch up!

- PS4 will have sold about 6 million in 6 months, so 12 million / year is easily doable. This puts the totals to 60 million for 5 years, and 84 million for 7 years. However, the price cuts will happen! A 25% price cut will include a comparable amount of sales increase, so 2-3 years down the line, you can expect 15-16 million annual sales, which brings the totals to around 70 million in 5 years and 100 millions in 7 years. And that's the minimum because it hasn't even been released in Japan and some other countries and it has been heavily supply constrained.

- WiiU is much weaker than Wii and if you read my ending note, I am estimating rather the low end of the given range (around 25 million or so), which is about 12%. Nintendo never did worse than that. Also price cuts will come, along with many AAA Nintendo titles. It will be the cheapest console all along.

Well, thank you for your valuable opinions. I am an economist, it's just fun and relaxing to apply my train of thought on hobby and fun stuff rather pure professional or academic stuff once in a while.

Also I always apply such methodologies instead of uttering my "gut" or "numerical wishes", as some tend to do. And it's true that my estimates are not necessarily accurate but the beauty of it is because each and every one of has a certain rational and formula behind it,

a) I can defend and reason with them

b) I can easily adjust & update them with the realities of the market

c) They are the expressions of the market realities and analytical breakdown of what's happening