I don't see console gaming being replaced by PC gaming. Non-technical users want something they can plug in and use, without tweaking graphics settings, resolutions, detail levels. PC games require that type of tweaking to look their best.
PC games also require driver updates and a lot of other maintenance tasks that are simple for techies (antivirus, system updates, hard drive defragmentation), but a lot of hassle for non-techies. I've seen people who have no antivirus because they had a demo version installed, and just ignore its annoying "PAY NOW TO ACTIVATE!" pop-up. And since it wasn't set to auto-scan, their antivirus basically does nothing anyways.
Even technical users like the idea of being able to play a game without tweaking anything.
This ignores that consoles are generally a LOT cheaper than a high end gaming PC, which you need to get the spiffiest PC gaming experience. Even a mid-range PC, say, $700 or so, is still almost twice as expensive as a console.
The biggest change I'm seeing is portable game systems are being replaced by smartphone and tablet games. Even if a lot of these games are mere front-ends for Zynga's cash receivers, most people REALLY don't care. They want games that can be played for a few minutes, then put away.
If anything ate console games, it would be smartphone games. I could see a future model smartphone with HDMI output and support for multiple simultaneous Bluetooth game controllers running a decent gaming experience.
Granted, the hard core techies are super picky about specs, but that's like how car fanatics obsess about particulars in their cars, but the rest of us only care about "Does the car get us where we need to go?" So most casual users, who make up the vast majority of the gaming audience, won't notice the difference.