I'm pretty sure you wouldn't want to play that game for long. If you want the real world, you know where to find it. People play games to have fun. To some degree (but much smaller than most people think), realism increases fun, but when it makes the game frustrating, boring and unwinnable, it's bad.
But you can make great games with more emphasis on simulation. For instance, Operation Flashpoint/ARMA(?) or the original Rainbow 6, where firefights are absolutely deadly.
