Why do we assemble merchandise we buy

I am on Sylvia's side on that one, NO,we should NOT have to assemble anything we buy. Congratulations to that hardware store owner, where if you look at something and buy it, the owner assembles it for you free of charge. I think that store should tell the world where they are located, oh yes, in Aurora, right? I wish they were closer to my place. That store owner deserves a medal.
A few years ago I purchased a sort of tent gazebo...supposedly so easy to assemble that a child could do it. They forgot to say a genius kid yes might do it with some adjustments but not a 79 year old "kid at heart". Well I tried to follow the directions, you know the story:"if all fails, read the directions..." This did not help me a bit. The manufacturer had everything marked wrongly. So do you suppose that I would make a trip to China to get the thing replaced ? No, I threw it away in the garbage, the metal collector picked up the metal bares that had all the wrong fittings and the trash collection guys took the rest to the dump. I NEVER again looked at something that I had to put-together.