Exactly. Not everyone enjoys the game the same way.
Having "better off track physics" doesn't necessarily make the game "better". Maybe more complete as a Sim, but for the ordinary player it will make no difference if it is the way it is now or ultra realistic. Maybe for some, ultra realistic physics might make the game too difficult to enjoy, leading to frustration instead of joy. We can't forget, this is a mainstream title/series. GT and Forza are the Battlefield and FIFAs of racing games. They could aim for ultra realism, but this games wouldn't feel fun for the regular player. Imagine ultra realistic FIFA? Pretty much unplayable for 10 min. matches. Or Battlefield, where sand slows you down compared to tarmac/stiff ground, you bleed after get shot, etc. That wouldn't make the game better, instead it would restrict the player base.
Both GT and Forza should still be the middle ground between full on Sims and Arcade games. Somewhat realistic to an extent, but without loosing the fun factor. The moment people acknowledge this, the fuss wont be as big as it has been. After all, the biggest complaints about GT5 and 6 were the sounds and the standards, for the casual player.