I love Linux. I've had some distribution or another set a second partition since the late 90s. It's great for basic usage and applications. Your average user will miss out on nothing by switching to Linux. But for me, it's not something I can use full time, try as I might. Games are a big part of it, but there are other things as well.
I'd say that the lack of Adobe's Creative Suite is a huge sticking point for me. I use just about every one of those programs on a near daily basis. It might work well enough in WINE, but that's not exactly the kind of experience most users are looking for anything. There are certainly no open-source alternative that stack up against Photoshop, After Effects, and Premiere. Hell, there aren't really any proprietary products that work as well as Adobe's suite does for most things.
We've seen the light of hope that is games before. I'm sure we all remember Loki Software. It was a great concept, seemed to have a ton of support, and the ideology was even spreading throughout some of the better developers, like Id Software. Then it went belly up, almost quicker than it hit the scene to begin with. I hope that's not the case now with Valve, as Linux has matured quite a bit. Still, the worry is there. They can either put the effort forth and force hardware developers to get in line, or they can fail. Really though, between a handful of Steam games and Minecraft, I would be covered in Linux. :P
Finding the solution to Adobe's absence is an altogether different problem though. They sell remarkably expensive software to professionals. They don't see the money in supporting Linux. The upfront costs would surely be high, and that isn't helped by the perceived unwillingness of Linux users to pay for any software, let alone pricey software. If they weren't in it for the money, they wouldn't be throwing out toy-like applications for tablets.