it costs a lot because it protects your head well. i'm pretty sure the receptor is multiple impact rated. this means with most helmets, you fall hard once, you either buy a new one or ski with a compromised helmet. the poc is built to take multiple beatings. the impact foam (stuff that protects your head) is twice as thick on my poc as my old red trace right above the forehead.
think of it this way: my friend ate it off of a wooden pole jam and landed on his forehead directly on hard snow. he got up, smiled and was totally fine. I can't be sure that the poc receptor he was wearing was to be credited completely, but with a cheaper helmet, he might have hurt himself.
you're paying for your brain's protection, to put it simply.