The ps3 will NEVER surpass the other two, in terms of world-wide sales. There's too much of a head-start. Assuming the ps3 were to get some killer app, the ps3 would still have to sell 3 times as many systems as the other two just to approach getting evened up with their sales. Then they would have to continue to sell at this rate for some time to make any kind of real lead. This just isn't realistically possible. I mean it's technically possible, it could happen, but a lot of really unlikely events would have to occur.
I would like to address this 10 year lifespan idea that sony throws around as well, because a lot of sony supporters site that as the reason the ps3 will be a success. Really? You believe that b.s? Ok let us assume that sony is right (and they very well could be) and the ps3 does have a 10 year life-span. Well the other two almost definately have 5--7 year spans, so when the ps3 "hits it stride" nintendo and m$ will come out with bigger and better consoles and people will be willing to spend money on a new console again. So sony will be left with a cheap platform with some life in it, but it'll be the inferior of the other two and have a developer support base that wasn't that strong to begin with. In the mean-time, sony still isn't making any money, due to poor software sales and a loss on every system sold. Nintendo makes a profit on every console and their first party sales are quite strong. M$ is doing fairly well, especially considering that they absolutely don't care if they lose money on the 360, just like they didn't care that they lost money on the xbox. Their strat is to bully out everyone else, as they can afford to. Sony could potentially do this, but seeing as they are a Japaneese company, rooted very much in turning a profit, it is unlikely they would implement this policy in the long-term.
Also, just a side note, but m$ will NEVER do well in japan. Sony, even if they came out with a turd with USB ports will ALWAYS do fairly well in Japan. Just accept this as a given. I hate to say it, but for lack of a better term, the Japaneese are very racist when it comes to foreign companies, american home electronics in particular. Even in the golden age when the american gaming company's were the only ones that mattered world-wide, the sales of popular consoles like the 2600 were fairly poor in japan. With that being said, the US is the major market, so you only have to do well in the US and not be a complete failure in Japan to be the world-wide leader.
While I don't think that sony is going to go out of business mid-cycle. (Although that is certainly possible.) I think we can all agree they are going to come in a solid 3rd this go around unless something major happens. Especially with the 800lb gorillias that are smash bros and what I predict to be insainely popular wii-fit have yet to be released in the US. I dbout they'll be console sellers, but they are new titles that'll have big sales, thus keeping the wii's library current into the next year. People say that the wii isn't competing with the others, but when you can only afford a single console (which is often the case with this new market) and you want a wii first, it certainly does. If anything, once the wii's supply issues are sorted out, I'd expect to see a noticable drop in sales of other consoles, admittedly hurting m$ (the other popular choice) more than sony.
Btw, SLion is quite right. I can name a game that the xbox can't do right now. Super Mario Galaxy. While the xbox was technically capable of doing it graphically, it wouldn't have been able to keep up a decent framerate like the wii as smg can have upwards of 60 enemies on the screen at a time with various lighting effects attached to each individual enemy, not to mention the world itself and mario and the game NEVER looses a frame. People look at smg at first-glance and think it looks like every other mario, but this isn't true. It's just unlike other companies (cough m$, cough sony, cough cough) the lighting and shading effects nintendo utilizes are quite subtle and not overly flashy.
Schmokes, I've gotta agree here, sounds like you are rooting for sony and making up excuses for them instead of sticking to the facts regarding the other consoles. There's nothing wrong with that, it just really hurts any argument you might make in their defense when you say things like that.