At this point the PS3 is just slacking off - Some mistakes were made in the main CPU design, for example. No DS because the put some kind of gyro in the controller, which won't be used by 99% of the games coming out. No actual improvement over previous game consoles except in graphics, and not even that much - and that's where GT:HD comes in.
At this stage, HD looks to be GT4 with a HD resolution option, and nothing else. Even if it gets an online mode i'll be hardpressed to buy a PS3 just to play 1 game - it *is* 600 bucks we're talking about, along the already higher cost of games for it.
I'll wait for GT5 (and Tekken 7) before i'll get a PS3 probably, there's no real reason to get one over the PS2 at this point - there's simply not enough new stuff to justify the cost, especially when looking at the state of my (now empty due to that icon below my name) bank account.