I pretty much tend to always be 2-3 years behind the current releases. Historically, this was because I was a broke kid, who had a clunky old computer, so I was pretty much stuck buying off the discount bins at Walmart and EB (remember them?).
Now, I still tend to do that, even though I have a real job and cash in the bank, and a decent desktop that can handle the newest games at max settings. 1.) Most games are pretty broken at launch, and it tends to take six months to a year to get the bugs patched up and the rushed stuff polished up to the point that the game is playable. And 2.) DLC. I don't mind paying $40-$60 for a finished game, but it boils my blood a little to pre-purchase, then pay another $100 or so to pick up the rest of the content that was held back and released in drips and drabs post-launch. Better to just wait for the GOY/Complete edition that has the whole game. I think I'll be playing Rome 1 and Medieval 2 for the rest of my life, but recent Total War games have given me a bad taste the way they are released with a fraction of the finished content playable, and then having to pay another $10 here and $15 there to unlock additional factions.
Then again, if I did nothing but play games for the next five years I don't think I could complete all the unplayed games in my Steam catalog already.