I fully understand your point, and agree to a certain extent. However, in a real car with own eyes, my field of view (including peripheral vision) is magnitudes wider than what my HD TV shows. Until I'm playing in a setting surrounded 180 degrees with HD screens, the dashboard view is no more realistic than the bumper cam, imho.
Truth... Driving a car through two letterboxes isn't quite realism... In a flight sim it's almost okay, because you don,t have to watch your wing mirrors for other pilots trying to punt you out of the air, but in a car, "cockpit view" shows you about 50% of what you can actually see in real life.
Yes, field of view is lower. But what then? Claiming that we should have bumper cam rather than internal because FoV is smaller on a screen, we could also make the argument that GT is absolutely NO more realistic than mario kart, because you're not feeling seat-of-the-pants sensations or putting your life at risk, or damaging your expensive car.
Any simulation has limitations and drawbacks based around the interface (PC, Console/TV, whatever). You need to take it to the limit of those limitations.
Even with bumpercam, you still don't see as much as you would, left to right, and you still can't look around, and you have a floating HUD. Yet simultaneously you see far more down than you should. I find it hard to beleive that a serious claim could be made that that is somehow more realistic than the FoV issues in the cabin view.
FoV isn't as much of an issue in a racing/driving sim. I can see just fine and drive the car to gold in license tests even with the interior view on. it's just compressed because of the screen size. But.... it's the same thing when I 'fly' an F6F Hellcat, enemy planes would be MUCH bigger, and easier to not only see, but also to ID, and I could move my head in 6DoF as well were I in the real thing - however, turning the 'pit off does not solve those issues at all, it actually makes things worse. (and I'm using a 19" monitor at IL2's native 1024x768 resolution with no FSAA [slow pc])
Are DS controllers realistic? Should we then throw out the driving model because the control isn't realistic? See where I'm going with this?
The real issue is to give up the advantage bumper cam gives, and that's what leads to justifications, because it's hard to accept a loss of an edge.
And btw, in an air combat sim, you absolutely do need to be cheking your mirrors, or even better, looking behind you. And just as if you are on the offensive and moving right, you probably don't have to worry as much about what's behind you, even MORE in a racing sim, if you are faster, nothing is "coming up" behind you. And let's face it, in GT, mirrors don't really matter unless you are trying to block (which just means you're too slow anyway), because if you merge and bump someone, no big deal, there isn't anything even approaching realistic damage, so just sideswipe the guy and push him out of the way - preferably into the sign at the tunnel of Grand Valley. I'm not saying I drive like that, but it's the same type of justification as claiming bumper cam is more realisitc - in ANY way.