^^ You forgot one thing though. As similar as the two might seem LFS holds nothing against the GT series graphics wise. And let's be honest, that's what makes the series. Plus LFS concentrates a lot more on the simulation aspect and the online part. It's just not not designed to simulate leagues or to have the occasional race against the A.I.
As much as everyone praises GT for physics etc., you got to admit that you wouldn't be playing it, if it had below-average graphics. There are tons of GT like games out for the console but not a single one managed to capture the flair GT features. Forza might have come close but it's still somewhat "raw" compared to the smootheness of GT4.