Valve is an unmistakable success story but the next chapter in the company's history is fraught with challenges and drawbacks.
If the Steam Box delivers to its fullest potential, then it will disrupt the home console space in a manner even more drastic than the Wii and the iPhone has. But there are crucial reasons why Valve, despite its unparalleled successes in the past, will not achieve this ambition.
Valve's grand plan, when stripped to its bare bones, is to sell an additional home PC that sits under the TV.
It's something that has theoretically been possible since the early days of home computing, though there's not been much sign of demand for it. Valve's hope is that there is potential for this kind of device, and all it takes is a compelling software package - like Steam - to convince people to make the purchase.
The first problem is cost. Valve has repeatedly claimed that the 'Piston' Steam Box prototype - based on the X7a micro-computer - is just one example of many different versions of the Steam Box. This may be because that the micro-sized X7a is not particularly powerful current-generation technology that sells for $999 - pricey enough for a household's primary PC, and nothing less than extravagant for a secondary model just for the TV.
Valve president Gabe Newell says the company's own Steam Box will be "quiet and focus on high performance", while marketing boss Doug Lombardi emphasised that many prototypes are "low-cost, high-performance designs for the living room".
How much Valve can bring down the cost of its PC builds, presumably while not selling at a loss, will be crucial to the device's performance.
As Digital Foundry pointed out in June last year, the cheapest high-end PC it could build cost more than £300, and how much Valve will save through trade bulk-buying (after adding its own costs) may not be so significant.
In November I wrote how Nintendo faced significant challenges with the Wii U because it is not focusing on a single audience or concept. The same is true for Steam Box. It does not have the essential features to outright replace the desktop PC, and it may be too much of a luxury to be bought alongside it.
Some may argue that, in fact, the Steam Box is perfect for console owners - the demographic who would most benefit from a more 'open' high-powered system - but Valve's audience, and by extension those who care about Steam Box, is a vast group of people who already have PCs with Steam installed.
For this PC-centric audience, an additional screen for Steam is desirable, but if they really want to add something new to their hobby then - ironically - their best bet would be a console. A new Xbox or PlayStation 4; a console with its own ecosystem, library and exclusive content.
Doubling up on something you already have, at the cost of several hundred pounds, is extravagant to the point of careless.
There is no doubt that playing PC games on the home TV is an attractive proposition. How this is achieved has always been the barricade. In an interview with The Verge, Newell said that streaming what the PC displays onto the TV, via a Wi-Fi service, was a good solution. But he said it was not as good as dedicated hardware, because streaming typically carries latency issues.
Valve is betting that the best solution is a device that will likely cost as much, or perhaps even more, than next generation consoles. In truth, solving streaming latency issues would have been a better puzzle to solve.
The Steam Box, like the Wii U, is a bold idea intended to appeal to two different types of gamer, in this case fans of both PC and consoles. Much like Nintendo has found, a device for both audiences often only highlights the depths of difference between each side.