To put it frankly, your arguement is flawed, highly flawed, however, you do have some points that can be elaborated upon.
I personally think Nintendo has a long legacy to go, Nintendo keeps its wits and despite having its down moments, manages to hold its own because the company as a whole is usually the market leader, they are innovative, they are creative and they demonstrate where gaming should take it's next turn. When you think about it, the only thing Wii lacks is online, and only because we've gotten to a point as humans where we rely on online facilities to communicate does this become a major issue, other than that, Nintendo finds ways to make gimmicks the new craze, to become less of a gimmick and more of a neccessity. You have to give a clap to Nintendo, not to mention the strongest of the three with first parties that make millions in thier own right.
On to Sony, Sony has held its own because it has a habit of copying, however, many of these so called copies are actually as good if not better than the original, but what makes PS3 special is the fact it integrates what makes Xbox popular and what makes Wii popular. Sony has had its downfalls, but it always overcomes those shortcomings and is racing towards being the second best selling console this generation, simply because Xbox's appeal worldwide at the moment isn't as great as Sony's. There are several reasons for this that I will go into in a moment when I discuss Xbox. Sony has focused upon first parties and continues to broaden it, realising that developers are only really making exclusive DLC nowadays and most of them go in the direction of Xbox, because Xbox is easy to develop for, it has a massive user base and Microsoft has BIG pockets filled with wads of cash to give away. However, Sony's new tactic works in its favour recently, because where they used to focus on third parties, thier first party games are now becoming the attraction, after all, would you prefer exclusive DLC for a multiplat game on Xbox or an entire exclusive game on PS3 WITH DLC? If Sony continues this, expands on this to Nintendo's number of exclusive titles and at the same time opens it's doors and welcomes third parties, Sony will stay in the game and even so much as pose the biggest threat.
Xbox now, Xbox is powerful beyond means but it's main issues at the moment are it too closely resembles the architecture of PCs, which is good in once sense because development is easier, but bad in another because....well, porting is easier too. My main problem was that many of the games I had on Xbox were also available on PC, and were the exclusives of Gears and Halo for examples enough to keep me on board, not really. If anything XBL is what I now miss because it was so functional, fluid and efficiant, something I don't get often on PC games but always got on Xbox. There is also the issue of games that were once exclusive like Mass Effect popping up on PS3 with better graphics, more modes etc, but just a few years later or even a mere few months, this is a pain in the arse, because while it's nice to have a game when it first releases, to PS3 owners, the year gap doesnt really mean that much, if they hadn't played it on 360, this is thier chance to do so on PS3. All that demonstrates is my point of third parties becoming less keen to make exclusives, for every third party Microsoft has formed a relationship with, so too has Sony, which basically means that Microsoft will need to adopt the Nintendo and Sony approach more and start making more of it's own first party exclusives. Other than that, there is no problem with the Xbox, Live is worth the money spent on it, despite Sony's offering, the games are fun and the console is good value. Microsoft will stay in the game as long as they have the money to keep going, the thing is, when Microsoft is making millions in a single second, they can afford to take more losses than the other two companies, you would have thought that with the massive loss on the original Xbox they would have bailed out, but oh no, they are still in the game and always will be once thier pockets remain deep. Not only that, Microsoft has realised that software cannot be it's only form of income anymore, it needs to diversify as a company in order to make money, and if there is anything you can give Micro credit for, its persistance. It will never back down until it has won a war, it wants to beats out google, apple, sony, nintendo, facebook and any other competitor it faces, and so far...Micro has been doing a pretty damn good job, may not be the best in any of those fields, but it is sure as hell determined to wiggle its way into becoming so.
Do I think Microsoft will be the first to drop out of the console race? The three titans? Hell no, not any time in our life time, thats for damn sure.