There's such a deep seeded, systemic bias against linux that it actually can never win, to any degree or magnitude, because the moment it starts winning we just move the goal-posts for the flimsiest of reasons to ensure it can't quite claim that victory.
Linux is obviously and clearly the most popular operating system kernel on the planet. Oh, no, that's no good a measure, servers are messy, let's refine it to most popular consumer operating system kernel? Oh... it, could also reasonably claim that title? No no, no Android, that doesn't count. Nope, No Chrome OS either, you can't have that, that's, well, that is linux, but its not. Just nice, pure, desktop linux, yes, perfect, arch linux, kde desktop, that'll never trend up and thus is the perfect new-new definition of desktop linu--wait hold up, I'm getting word this is, not possible, its actually SteamOS? Nope, kill it, that's not desktop linux either, kill it.
Or is it? Whether or not we have come close to TYOLOTD depends on how you define "The Desktop". If "The Desktop" is a metaphor for "the hands of the non-specialist user who doesn't even call their device 'a computer" then yeah, it's doing great. The Deck is a major step forwards in that, it wraps up Steam's entire catalog of Windows games into a nice little bubble of virtualization that varies in seamlessness depending on how new the game is.
If you define it as a desktop computer, it's nowhere near that. Most people who sit down at a a desk with a large screen to do work that involves multiple windows and a mouse pointer are still sitting in front of a box that's running Windows or MacOS. Those two operating systems still dominate that domain, as well as the world of people popping open a laptop to do windows-and-pointer work away from their office.
Linux keeps nibbling at that domain, and the work Valve did on their fork of WINE to get fifty bazillion Windows games running on this handheld Linux device is probably going to help take some bigger bites. But what do people go buy when they want A Computer? When you answer that with "Linux", that's The Year Of Linux On The Desktop.