It also sold 11.5 million in 2011 which is just about 2-3 million less than PS3/360 did that year which was also the peak year for both them. I would say it was an attractive product for 5 years.

I think that's the most any console has sold in one year and likely the most any console will ever sell in one year which is impressive, but when looking at the overall big picture, that one year represents almost 25% of the console's lifetime sales, which really just illustrates that demand for the Wii was spurred by broader demographics that lost interest in the product after 2010. 

The 24m must have been for 2009 as sales for 2010 were about 17m, followed by 11.5m in 2011 which represents a pretty sharp drop off and a an extremely fast peak. 

Playstation consoles have all trended differently, making 10 year + production cycles viable. 

These sales are not completely for games from gamers, its from casuals who found the wii motion controls unique with the games Wii Sports etc., But PS4 sales are only from hardcore gamers and its about games and faith in Sony exclusives support in future.

PS4 hasn't reached it's peak yet, but I don't think it will reach those numbers in one year.

There was one trend that gamers used to look forward to on PS consoles and that was aggressive price cuts due to competition.

The original Playstation had a price cut of -$100 only 8 months in, reducing it's launch price by a third from $299 to $199.

The PS2  also had a price cut of -$100  1 year 7 months in, reducing it's launch price by a third from $299 to $199.  

The PS3 had  a price cut of -$200 1 year 10 months in, reducing it's launch price by a third from $599 to $399.

It's hard to say if Sony will continue this trend of price cuts of 1/3 before the end of the 2nd year now that it faces no real competition..

I don't see PS4 cracking 20 million TBH.

Despite all these factors its trending far above the PS3. Your thoughts really have no basis to them.

Oh and I just noticed you're a Nintendo fan. Lol whenever I see someone making a prediction similar to yours they are almost always Nintendo fans.

And that peak could've been more if it weren't for the supply. The Wii's peak was phenomenal for the industry, but for me nothing beats what the DS was able to do.

PS2 and DS have sold about the same number of units, with the PS2 selling much more software.

I dont think anyone expects PS4 to do those numbers in any 1 year, but thread it still a bit premature, PS4 has not even had a peak yet as its not even had 1 year on the market to set a baseline for itself :P