Production line? Come on. This is not Ford motor company churning out racks. Most of these companies maintain a small staff and build orders as they come through. I would gladly build my own rack, like I have in the past, but I don't have time. Im going to order from Beeger Boxes and wait for the shipping.
Also, have you never see a radiator heating element in an older apartment building? As the coils heat up its not transferring heat energy to you via the floor or any physical object. Its heating the AIR. Just like a heat pad heating up a small insulated tub. With the correct size heating element you can maintain ambient temps just fine. Sheesh.