That is like calling someone out for buying a house. Of course you can buy all of the parts cheaper and build it yourself for a looooot less than what you would pay for a built one. To further the point I am pretty sure the framers who built the house didn't chop down the tree and plane the tree into studs to use on the house, so they are not legit? No, they used what was available sourced it at the best rate for the quality and market it as such and stand behind the product. I am not sucking anyone off, consumerism is very much a thing and I don't have the time to build a house so I will pay the premium to have an already built one.
And what I am absolutely positive about is that you have never thought of designing these fixtures until you stumbled your arrogant ass in here thinking that you were revealing something we didn't already know.