Seven or eight PS2 games, still no system. I'm like that with music, too; I'm a short termist. Instead of saving up a grand or so to buy a proper set of direct drive turntables, I spank more than I can afford every month buying records that I absolutely cannot be without. Similarly, when I see a used Ico special edition in good nick, the willpower required to save up the money to buy a system to actually play the damn thing on seems to recede over some sort of horizon.
So mainly it's a budget thing. I would have a PS2 if I could ever seriously meet or justify the outlay, but I'm happy to wait even two or more years to pick up a decent second-hand one for say £30. That's how much I bought my PS1 for, and it still works fine. By the time I buy a PS2 I'll have shitstacks of great games to play through on it, and to me (as a scabby no-mark pauper) this seems to me to be the game-acquisition model that makes most sense.
There was an excellent thread on this some time back, started by a guy who (I think) was planning either to give up games for good, or buy and play games a generation behind everybody else, due to the fact that he didn't really feel he was getting his moneys worth running to keep up with generational trends. I sympathise a lot with this; I sometimes feel we're all being hoodwinked into parting with a lot more cash than is really necessary. However I won't try and pretend I'm some kind of master-economist: as I say, I'm just too weak and lazy to even rise to the bait.
