The ability to run dedicated servers would be a necessary step in allowing user-created content (multiplayer mods being very popular). It would not only free console gamers from matchmaking, but would also open up your online play options: tailored servers for people who prefer to play in a particular way, clan servers to practice and scrim on, a cool multiplayer pirate mod running on the back of a modern warfare game. All of the advantages that PC gaming now has.
To this end, there needs to be an industry-wide agreement on the minimum required spec. Presently the spec changes depending on the requirements of each game, which means there is no standard for PC publishers and developers to work towards. Even one's understanding of what the minimum required spec means differs between people. I and most others believe that it refers to the absolute weakest system that can run the game reliably, while others (like the people defending the buggy release of Black Ops on PC) believe that it refers to the weakest possible system on which the game can be expected to start up. Between these two definitions lies a gulf.
The standard minimum spec should be built with components that are cheap and easy to find. It should be a low- to medium-end rig, and a smooth framerate should be guaranteed for this build by all publishers, who will hold all developers accountable to it. I went into PCCG and planned such a machine in just a few minutes, and for under $450. Aside from the graphics card, this system is probably weaker than the computer most of you are sitting in front of; even the processor is outclassed by the quad cores that are now showing up in netbooks.
If you're willing to get a weaker graphics card like a GT430, the price comes in at less than $380. I built a machine proportionally equal to this one four years ago (taking hardware improvements into account), and I spent those four years playing pretty much every new release successfully on medium quality (basically console quality), with the exception of games like GTA4, where the developer didn't do their job properly. Both of these listed systems are DirectX 11-ready, too.
What this means is that in the years to come, the dividing line between consoles and PCs will begin to dissolve as they each evolve to be more like the other. Programming games for the PC will become as predictable as programming for a console because the standardised minimum spec will allow everyone to design systems according to their budget that can be relied on to play new releases for years to come. Consoles will become more like specialised PCs in their operation because of the requirements of running and developing user-created content and open online services.
And when we get to this point, we no longer have PCs vs Consoles, but two kinds of PCs running specialised operating systems (which may even just be different versions of the same operating system, where the Xbox may be likely to run a modified version of Windows).
Many developers are also too lazy or not prepared enough to allow their games to be modded, such as DICE with Battlefield: Bad Company 2. There is also the idea that allowing the life of a game to be extended with community mods slows down sales of newer releases; after all, people are still playing the Project Reality mod for Battlefield 2. This idea is fundamentally wrong: people play those old mods because they are better than even the newest games. The Infiltration mod, which was released back in 2004 for the original Unreal Tournament which came out in 1999, is still more realistic than every single 'infantry simulation' game that has been released since, including the ArmAs and Operation Flashpoint: Dragon Rising. If developers were to create a game that surpassed it, everyone would be all over it.
For the PC, its biggest hindrance is also its biggest strength: the decentralised nature of PC gaming. While a hardware producer like Sony or Nintendo can enforce a standard of quality on the games that are released for their console, there is no such enforcing body in the world of PC gaming. Various attempts are underway to get some standards in place (the PC Gaming Alliance, for example, as well as Valve's own efforts when it comes to games built on the Source engine) but these rely on publishers and developers cooperating for their own good.
What's certain in all this, though, is that just as the drive to play is strong in all people, the urge to create is stronger yet. All games are moving towards the common goal of greater freedom and more opportunities for creativity and emergent play. Hardware will move with them.