A few years ago I ordered two of these The description did not mention self assembly (I see it does now, since I complained), they came as a pile of planks with screws, not even pre-drilled. However I got out my trusty tools and managed to do the job in an afternoon. It was very satisfying and they are still standing!
I actually enjoy putting together furniture, but I once assembled a complicated desk in the living room, for my then husband's study, only to find it wouldn't go through the door! I then had to take it apart and do most of it again. Very frustrating!
I think many people would like the option of buying items ready-made for a small fee.