I thought exactly like that when I was thinking of buying a console. I thought I already had a decent gaming grade computer so why a console that the games are so expensive for?
I eventually bought a PlayStation 3 and I couldn't be happier. The strategy I followed for last 6 years was easy - pre-owned games - if you are in USA/Canada, pre-owned games have a huge market and they drop in prices at least by half in about a year if not sooner, depending on the genre of the game. The PS3 exclusives alone made the purchase worth it. I don't think on an average I paid over $18 for ANY game I have. Now that's significantly cheaper than any PC game.
Some games like The Last of Us, DBC 14, Fifa 14, GTA V etc. I had to buy brand new and they are going to last for a long time.
On the other hand, PC graphic cards do start showing their age sooner than consoles as most games are built as a PC showcase. If you built a PC in 2010, try running a game released in 2014 on maximum settings and you'll see what I am saying. On console games, this rarely happens - yes some games drop in eye-candy department, but they will still be quite enjoyable. Watch Dogs is the first game I thought showed PS3's age clearly but that is happening after a whopping 7 successful years worth of gaming and it's also not the best coded game if you ask me. But just a year ago, The Last of Us showed us what console platform optimization can do. I am sure XBOX also has similar examples to make the point.
Finally, just the feeling of collapsing on your couch in front of your big screen TV holding a wireless controller playing a game WITHOUT having to go through those clunky operating systems and installations first is priceless!
Clunky operating systems and installations, have you used a PS3 or Xbox 360?
Speaking of graphics cards showing their age, you'd have heard of watch_dogs right? I nearly cry with laughter looking at the developing mess there. "Definitive next gen experience". It's already shown that the PS4 and Xbone aren't even up to scratch, let alone the PS3 and Xbox 360 (which sadly look awful compared to the PS4 and to a lesser extent Xbone). There is a world between FIFA 14 on the PS3 and PS4. Even the last of us suffered from the PS3 though (hence the PS4 version coming soon).
The consoles pull is that they are a cheaper options using standardized settings, but the fact that they are already well behind the eightball within a year of their release shows the issue with them being "'bout da graphics" as so many people I've talked to have said. To be completely honest the only console that even have decent games coming out at the moment is the Wii U (and the only next gen one to have a library that justifies its existence).
The real issue for consoles though is the rise of platforms like steam and gog making games extremely affordable on the PC, with accounts usable between multiple (of the owner's) computers, along with save data and settings for the most parts. With there being very few exclusives (bar Nintendo, which is virtually entirely exclusives) and a failure of "da graphics" side of the next gen consoles, it'll be interesting to see where things are at the end of this particular generation.
Speaking of "significantly cheaper than any PC game" at $18, here are some games you can pick up for under $18 on steam right now:
Borderlands 2 + Borderlands GOTY: $9.99
METAL GEAR RISING: REVENGEANCE: $14.99
Tomb Raider (the new one): $4.99
Dragon Age: Origins - Ultimate Edition: $7.49
Mass Effect Collection: $7.84
Fallout: New Vegas Ultimate Edition: $6.79
Injustice: Gods Among Us Ultimate Edition: $17.99
Fallout 3: Game of the Year Edition: $5.36
Sleeping Dogs: $9.99
Goat Simulator: $7.99
PAYDAY 2: $9.89
Portal 2: $9.99
Grand Theft Auto IV: Complete Edition: $8.99
The Elder Scrolls V: Skyrim - Legendary Edition: $16.99
So no, that is categorically untrue. Brick and mortar stores might bend you over a barrel backwards money wise most of the time, but that's why they're slowly disappearing, even the consoles are looking to phase them out from what I can tell. Anyhow, if you go on steam, I'd personally recommend:
Don't Starve: $8.99
Octodad: Dadliest Catch: $8.99
Super Meat Boy: $5.49
Banished: $14.99
All of those are fantastic, on the couch in front of my TV. Might not be to everyone's tastes, but pretty damn good games.