The reason it's all so expensive is coz it's labelled MTB.
The MTB market is extremely small in comparison to a lot of other sports (eg. MX) and because of this the prices are much higher.
If the market was bigger, then the prices would drop coz the companies wouldn't need to charge as much to make the same profit margin.
Take a look at some MX gear next time your in a MX shop. The roost deflectors are only about $150, they offer pretty much all the protection you need in my opinion, (if you already have elbow/arm guards).
But that's just my 2cents.