I've wondered the same thing many times.
Most of the items I want, such as a 6.8 a2 flash hider is rarely available on site. You have to order, charged for shipping and then as in the last order I had, will be refunded as long as you are persistent. I had to email, IM, and stop by the store three times to get mine. Only took me 32 days.
It would save psa CS time if I didn't have to keep pestering them about a few bucks. They could tend to other orders and maybe catch up.