One console would be at best, wishful thinking. I will explain why:
First and foremost, it would be illegal in North America for several companies to formally agree to sell and develop for one console. Why? Because it could be considered a monopoly and gets into price fixing. Having any sort of legal or contractual agreement between the companies to produce/support only that product would not be allowed. Simply put, if it were the only console, the developers could charge whatever they want.
In this situation, in a capitalist environment one of two things (or both) nearly ALWAYS happens.
1. Companies can form unofficial, or unspoken agreements. These are technically illegal, but there is no easy way to prove they exist. So companies A, B and C get together and verbally agree on a business plan and have to 'trust' each other. Now if one company were to break the agreement, say company B decides they are coming out with their own console secretly to make more money on their own. There can be no legal retribution from A and C towards B. So there is a big temptation.
This is call "Prisoners Dilemma", from wikipedia:
In its classical form, the prisoner's dilemma (PD) is presented as follows:
"Two suspects are arrested by the police. The police have insufficient evidence for a conviction, and, having separated both prisoners, visit each of them to offer the same deal. If one testifies (defects from the other) for the prosecution against the other and the other remains silent (cooperates with the other), the betrayer goes free and the silent accomplice receives the full 10-year sentence. If both remain silent, both prisoners are sentenced to only six months in jail for a minor charge. If each betrays the other, each receives a five-year sentence. Each prisoner must choose to betray the other or to remain silent. Each one is assured that the other would not know about the betrayal before the end of the investigation. How should the prisoners act?"
When this example is applied to businesses in the real world, most or all of the companies will attempt to break the deal for their own benefit. Even if collectively it will hurt them all. This is how you get ahead in business. It's what happens when one of the companies does not have some sort of 'big stick' to wave at the other companies if they get in line. An example of this is OPEC, whom one of the 'countries' has the ability to put the others out of business should they attempt to break the agreement.
In gaming there is no such big stick. In-fact, the 2nd thing would happen regardless.
2. Another company would come along, and make a console that does things people wanted the one console to do, and people will buy it for that. Attempting to make one universal console would only open up more of a market for an alternative one.
So, thats why I believe it could never happen. And even if it did, (my opinion, i can't say forsure) the one company would probably be less obligated to put out new features or make the console of any quality to begin with. I would prefer the continued advancement of technology to get more buyers, not a stagnated console. So i would not care for that option anyways.
As for the network console posted above:
It's an interesting concept, but I don't believe this will be the 'future' of gaming. It may very well have a market, but it's no means a step to a Universal Console.
The biggest flaw is the one mentioned in the article. You will need a decent, if not killer internet connection to be rocking out these games even in standard definition. I don't care how big of server farm this company has, you still have to have access to, AND PAY FOR a good connection. If any of you pay for your high speed internet you will note, that this is not cheap.
Not saying its not a good idea, for certain people this is a good idea.
As for the price, it may seem like your getting a good deal, but you really need to think about it. It's the whole 0 dollar cellphone idea. You have to pay to subscribe. The effective cost of this system is higher then the playstation 3 after you've had it for under a year. People complain about the cost of a Playstation three, but think about it.
PlayStation 3 = 399.00 Canadian + (plus internet connection, if you want to play online)
Xbox 360 = 299.00 but 109/per year for xbox live, so if you want online play, 2 years later its more costly then the PS3. (plus connection fee)
Live Box = say $100 dollars, + subscription fee + internet fee per year
So look at the 'effective' price of these consoles over the time you own them? No one console can meet all the needs of one gamer. Say your going to buy an internet connection anyways, or perhaps your area cannot get affordable high speed internet? The console you choose will depend on your situation.
However it is impossible to say its a cheaper solution, unless your only playing your live box thing for a year and tossing it out a window, infact its easier to say it WILL cost more. At least 5 years down the road, i can blow the dust off my PS3 and Xbox, slam an old game in and play at my farm.
End of Essay.

haha