My reason is simple...The games.
Has very little ( if nothing ) to do with the cost of a computer, the constant tweaking, driver issues..etc. That stuff comes with PC's. I knew that when i got into them. So headache of computers isn't a factor when it comes to me owning consoles.
Again, my reason is games. There are MANY games that simply do not, and will not be ported to PC. And even if they are, the PC is not the platform to play them on. Has nothing to do with how bad most ports are, but more to do with the fact that a Keyboard and mouse just doesn't work on many games.
I'm a big fan of RPG's. JRPG's to be specific. the good ole turn based style. I couldn't imaging trying to play them on a keyboard for an extended period of time. And if anyone here has done any emulation with old RPG's on their computer, then you should understand.
Also, a lot of the Action games, such as Devil May Cry, Onimusha, God of War...etc have the same problem. they keyboard and mouse just aren't designed to cater to those types of games. Ontop of that, the 3 games i just listed are fast paced games, and the LAST thing you want is a massive FPS slowdown when fighting 10+ enemies, or a strong boss.
Yeah, a controller can be plugged into the PC and used. And I can hook my PC to my TV without any problems, as they are close enough to one another. But you arn't going to see the new Final Fantasy, or the tales of, or the Metal Gear series popping up on the PC anymore.
It comes down to exclusives, and when they are ported, the keyboard and mouse tend to suck, and console to PC ports tend to be shoddy at best.