I think I'd have to agree with Chuck that 6-8 hours is probably not all time spent on the rack, unless you're doing a lot of hand carving or engraving.
If you're comparing to mass produced items, the pricing isn't apples to apples either. If you mass produced items, you'd probably get discounted prices on woods and other materials for the quantity. You'd also be building in a assembly line method of producing several at once, which probably would cut a lot of time, but add some overhead depending on the space you had to work in.
I think one big factor is in the cost of materials, it can add up quickly as the price the average hobbiest pays for wood and other materials can be quite a bit more than what a cabinet shop would pay that buys in larger quantities.
To a small child, the perfect granddad is unafraid of big dogs and fierce storms but absolutely terrified of the word “boo.” – Robert Brault