The MMORPG equalient of this would be if you buy the game, and instead of earning anything in game, (no loot no money no nothing) you have to buy every single piece of armor you want (and it would ofcourse be made level restricteD)...
But if you dont keep paying every month (which pays for servers, and pays the developers for delivering new content like weapons and levels) you dont get to play at all. Not to mention the usual initial cost of 50 bucks before you can play at all. With this (GT:HD) you could plop down how much you want, and play forever. Nobody is forcing you with this, with an MMORPG your forced to pay to play.