Hmm PS3 has sold 4 million more then 360 had last year.

[RVDondaPC]

Of course there are other factors to be considered and they do have effects on the different consoles and the life cycles but external factors are pretty even and consistent for the different consoles and the internal factors(if given an advantage or disadvantage) would be rather constant for the lifespan of a single generation.

For example the factor of the economy is important and it currently makes a lot of people price sensitive. However, the economy doesn't change over night and the poor economy looks to persist throughout this generation's life cycle so it would lead one to believe that the trends of the past years will continue and not be altered by the economy. The price advantage that the 360/Wii have had look to continue, however as the price gap is closed the advantage looks like it would be reduced. But of course I don't think you will ever see the PS3 having a price advantage over anyone so you would assume this advantage over the course of the generation would persist for the 360/Wii.

Internal factors like the Video game libraries also have a great advantage for given consoles but generally over the course of a generation they stay consistent. For example the GTA series and FF series greatly helped out the playstation brand in previous generations and that advantage was maintained for that whole generation. Come this generation, they both have gone multiplat and have taken away that advantage, however the PS3's success(relative success) early did not depend on that exclusivity of those games so you can assume it's effects this generation will be maintained. As far as advantages for first party exclusives you can only assume that those factors will stay consistent.

Most of the internal factor changes happen between console life cycles that's why the PS2 and the Game Cube's success(again relative success) is not very indicative for the success of the next generations consoles. However once a generation starts the trends start to reveal themselves and the external/internal factors start to become stable.

I don't want to dismiss the idea that external/internal factors do play a part and can influence sales over a given period. But I do feel that by this point into the generation it would be rather surprising if something did come along and drastically change the landscape of the console wars and alter the trends that have been revealing themselves for 3 years now. It is possible though.

You do bring up an interesting point about it only applying to a generation and not a specific console. I only find it interesting because I don't remember there being such a similarly featured set of consoles as the PS3 and XBOX360 since maybe the Genesis/Super Nintendo. If we do look at the past it does not apply though, the PS/N64/Saturn consoles started and declined at significantly different time periods and at different rates. The PS's life cycle was almost double that of the other consoles in term of significant sales. And again the XBOX and PS2 both started and declined at different time periods, with the PS2 again more than doubling the life cycle of the competition. But because the 360 and the PS3 are so similar there may be some merit to that point but looking back at history there is no evidence that a generations consoles start and decline at the same rate for all consoles.