Why are equipment racks so expensive?

I periodically look through the racks in the sales section and I cannot get over just how darn pricey those things are.  I don't get it.  

I mean I see racks that cost 1, 2 or even 3K.  Really?

I've currently got two Ikea end tables stacked (not the Lack but some other ones) and they work rather well but sometimes I look just to see what's available.  I see the prices.  Then I'm back to being happy with what I've got.

So...why the prices?