It can be very 'similar' to the real thing.. you just need a lot of very expensive addons!
the default stuff is absolute crap. The addons are where the real 'realism' is.
http://img55.imageshack.us/img55/8224/56321082wk4.jpg
screen of a 737NG i've got coming into Kai Tak.. a far cry of what most people percieve MSFS is like, perhaps?