I see it somewhat differently, IMO the Linux gaming revolution is an ongoing process that multiple parties have contributed to for more than a decade, rather than a singular event. The Steam Desk is the latest product of the Linux gaming revolution, it builds on past achievements and paves the way for new ones in the future.

I’m no Linux historian so perhaps I’ve got something wrong, but this is my list of significant achievements that have contributed towards the Linux gaming revolution:

• Loki Entertainment (1998). This is actually something I learned today… I had previously seen LE’s ports of games to Linux as somewhat of a failed experiment, as the company went bankrupt in 2002 without any apparent long term effects on Linux gaming. However, their wiki page brought up that they developed several tools that have been useful for many other Linux game devs, and some of their former employees went on to work other Linux games.
• Ubuntu (2004). They made an effort to make desktop Linux more accessible, and by becoming the de-facto mainstream distro they gave game developers a single release target that covered the majority of Linux users. It might not be ideal from a Linux/FOSS perspective, but I think it would’ve been difficult to get a lot of game developers on board if they had to support multiple distros. They have since lost their importance for Linux gaming but at least they deserve a spot in this list.
• Wine (stable release in 2008). Not very usable for gaming at the time of their 1.0 release, and it might still not have been without Proton, but development of Wine began as early as 1993.
• Humble Indie Bundle (2010). IMO this pay-what-you-want bundle was the real beginning of playing games on Linux. There had been some attempts at releasing games for Linux before of course, but I think HIB showed that there was a demand for games on Linux and that Linux users were willing to pay for the games. Buying all the HIBs gave Linux users a decent library of quality indie games, and at least to me it seemed like indie devs became much more likely to support Linux and Mac after this.
• Steam for Linux (2013). Proprietary app stores and online DRM is another thing that doesn’t sit well with a lot of Linux/FOSS users, but it was definitely fundamental for AAA gaming on Linux. Valve also released the Linux version of The Orange Box in 2013.
• Steam Machines (2015). While failing to introduce Linux gaming to the masses, they brought SteamOS and other technologies that would later be used in the Steam Deck. One might even argue that the Deck is just the next iteration of Steam Machines.
• Proton (2018). A result of the work of Wine developers, Valve and CodeWeavers, this is of course what allows us to run Windows games, often as smoothly as if they were native.
• Steam Deck (2022). Leverages the previous achievements and packages them into a product that turned out to be attractive even to non-Linux users.

Valve (and others) have really put in a lot of effort to make Linux gaming happen, but my point is that the Steam Deck isn’t the one singular thing that we can thank for Linux gaming. It wouldn’t have brough any kind of revolution if released in 2016 (see Smach Z for example), and if the Steam Machines were released in 2022, perhaps they would’ve been just as successful.