$6000 for a gaming PC is beyond ludicrous. Anything you find for that price is going to be using components which are terrible value for money, plus a hefty premium charged for the Alienware brand. I'd never buy an Alienware or recommend that anyone else should. $1500 would be quite enough for a very good PC, component-wise:
http://techreport.com/articles.x/21876/6
A good gaming PC is also a good PC for other uses too, of course. And, while a gaming PC does cost more than a console, now that the current generation of consoles are getting long in the tooth (the graphics chips in both the Xbox 360 and PS3 are derivatives of PC GPUs which are now a few generations old), the difference in graphics can be noticeable. This is mostly because, if I play a game on my PC at 1080p, it's rendering every one of those 1920x1080 pixels, but on consoles, it's normally 720p or less scaled up. Look at this in 1080p:
http://www.youtube.com/watch?v=o921p4TIzH4
You're paying more, but getting more too - it's a choice. And it disappoints me when I see people using "I want to sit on the sofa with a controller and play on my TV" as a reason in favour of consoles. PCs can use controllers and be hooked up to TVs no problem.
Consoles and PCs are both valid choices for different reasons, both with their pros and cons.
This.
And I would add, that games are overall less expensive for PC, so with time, you save money in comparison. Also, I would love to put in some numbers of consoles that break, or die, and need to be replaced (like an average lifetime of this gen's consoles ?).
At last, needless to say, but you don't have to use a high-end geared PC to enjoy games, and moreover, you can buy PC components off from other people who are upgrading their rig.
You don't have to buy the latest wireless quantic fusion mouse & KB, there are also normal mouses and KB that are enough for gaming, especially if you aren't going in the competition scene. This is why the budget argument is, I think, completely off-target.
While it's true computers can give a hard time to maintain, it's also because of the variety of different possible combinations and choices. But choice is freedom. Think of it like a bethesda game : huge, open, possibilities all over the place, but hard to make completely bug-free, and even more enjoyable when you can tweak it a bit.
If people like TES games, I don't see why they couldn't like gaming on PC.
There are also all these marvelous indie games out there, it's a shame that when we talk about "gaming", most people only think about big blockbuster AAA titles and the like. Gaming isn't just these. Open your mind and challenge you certitudes... or maybe that's too much to ask.
I have PC and consoles, but if I was short on money (like when I was a student, or like many friends I know today), I would only be on PC.