^^
Yes, it's confirmed you don't understand the difference between "it's not granted that a thing will happen" and "it's granted that a thing will not happen".
I won't explain it again.
But about the points 2-4 it's just as simple: we can't know for sure, it doesn't mean it won't happen, but we don't know with enough precision, yet, what Nintendo, Sony and MS will do next.
About the part
And just as for Nintendo, nothing can grant they'll manage to stop disruption, but they MUST try.
Nintendo is the disruptor. Why are they trying to stop disruption. They are stopping the counter attack
Microsoft and Sony are not disrupting.
"They" was referred to Sony and MS, sorry if I wasn't clear enough.
About point 5, and all the stuff about disruption: again, we will know quite soon what kind of counter-attack MS and Sony will do, but now we don't have enough details. And we still have to see their actual effectiveness, whatever kind of counter-attack they will happen to be.
The article by Christensen mai kindly posted answering me http://www.forbes.com/2007/08/01/sony-games-innovation-lead-cz_cc_0802christensen.html is about what Sony could do and it's quite clear, it's also clear that if Move and its games are definable as a "me too" reaction, it will be the weakest possible counter-attack amongst those that Christensen lists in the article, but we don't know every detail about all this yet. and we dont' know how the public will react, yet. Even less we know what Sony, MS and Nintendo itself are preparing for next gen. I admit that up until now disruption worked very well for Nintendo, but for the future, I am neither Malstrom nor Pachter and I haven't got a crystal ball.
My point is just that we haven't got enough data for the future, I'm not dodging the questions, my answer is just "we can't know with enough precision, yet".
So when you state that you are sure about how disruption will proceed, I can answer you neither "yes" nor "no", but just "maybe", or to use a phrase that appears to short-circuit your valves, "it's not granted". 
Edit:
You cite:
"When the incumbent has retreated into the highest tiers of its market and has to fight because there is no room for further retreat, it is at a competitive disadvantage. As the game changes to the one the disruptor plays best, it is very hard for the incumbents to develop new skills quickly."
From the very pen (or keyboard) of Christensen, two simple statements that don't contradict what I'm saying: the first one is, can we say with absolute precision the incumbent retreated into the highest tiers of the market? Up until now, it's more like Sony initially chose to avoid fighting Nintendo and instead it fought MS for second place as soon as economies of scale and widened SW library allowed it. It cannot be considered a retreat, because the market was growing and still is, although slower, and also because Sony is persuaded some PS3 features give it a market that is at least partially independent from Wii's and XB360's ones: we could even say that Sony had since the beginning some skills and values Nintendo hasn't, multimedia player capabilities, although they were eventually revealed as less lucrative than Nintendo's ones and Nintendo isn't by any means interested in them.
The second is the bolded part, that's precisely what I'm saying: the game changed to the one the disruptor plays best and it's very hard for the incumbent, etc...
Very hard, NOT impossible, very hard means Nintendo has good chances, not absolute certainty of victory.
BTW, the article you linked proceeds mentioning also cases in which the disruptor doesn't succeed and cases where disruptor and incumbent fight and hurt each other without a real winner but with actually two losers instead.
What you'll never find in Christensen articles (or in any other economists' ones) is absolute certainty, because he can accurately describe and predict what will happen when the initial conditions are met and if disruptor and incumbent follow the typical behaviours he observed before, he can check whether in current cases the conditions are met, but he can't tell for sure three things: whether in current and future cases disruptor and incumbent will keep on following the typical behaviours and, in future cases, not even if the conditions will be met again.
If you read the last parts of the article you cited, he proceeds also roughly describing some cases in which the incumbent's reaction can partially or totally succeed.
But let's also read another part of that article:
A) By the time the Bell companies firmly established themselves, they developed unique competencies related to transmitting the human voice over relatively short distances. They established skills in acoustics, network management, customer service, and so on. Western Union had none of these skills. Its business did not need to solve these problems. It was on the wrong side of asymmetries. Western Union couldn't suddenly become a viable competitor after the telephone had been improving for twenty-five years. Similarly, Digital Equipment Corporation couldn't match the flexibility of the personal computer assemblers' processes, Sears couldn't match the inventory turns and low prices of the discount retailers, and so on.
B) It is important to note that almost thirty years elapsed from the introduction of the telephone before telephony operators began making serious inroads against Western Union. Similarly, wireless telephony existed for twenty-five years before it seriously began to erode the wireline business. Both innovations grew for a very long time in markets that were different from the incumbents' cores. Incumbent firms that take action when data shows a downturn in their core businesses take action too late. The only signal to take timely action is sound theory.
A) Sony's and MS' situation is that their skills are not as dramatically outdated or even worse absent like Western Union's, DEC's and Sears' ones were.
B) The long timespan of some disruptions can change things in unpredictable ways: while in telephone vs telegraph Bell managed to enjoy a very large part of the success of the disruption it started, in the case of cellphones vs wired phones not in every country the disruption fruits were gathered totally or partially by the companies that started the disruption.
There is enough just from these things, to say that we can't be 100% sure.








