I'm a PC gamer that games 90% of gaming on PC games. PS4's a great deal.
You can build a cheaper PC than listed and match X1 quite closely. You can use your old controller on PC as in dualshock, or x360 controller, you don't have to update that every console gen. If you've never gamed before then I guess you have to buy it.
Windows 8 isn't included either. You're not going to game on linux, unless you just like making things difficult for yourself with wine and a small amount of games. But, I've gotten free licenses in microsofts dreamspark program, etc. It's a cost they didn't list.
The PS3 is excellent bang for your buck for gaming, barring RROD type issues which made my 400 dollar xbox 360 an 800 dollar xbox.