I find it hard to imagine how someone could ever become a good player without studying, by which I mean book learning and active, educational discussions like we get on FTR. I guess someone could simply learn the rules, start playing and over a long period of time pick up the necessary strategies which make a winning player, but it'd take a LOT of practice, not least to lose the bad habits that they wouldn't have anyone to talk them out of (I remember my own logic for playing K9o - it could make a straight! - and I might still be playing it today if it hadn't been for FTR and Small Stakes Hold'em).