It's very much a case of purchasing an item of furniture to suit a desired need.
So in the case of a corner sofa we're talking function over form. To assemble and arrange a two piece suite in a room takes a greater degree of thought and effort than simply sticking a soft squashy thing in the corner of the room. It's basic and quick.
Much the same way a chav eats at KFC/McDonalds they don't have the desire/effort to strive for something better.
Ah ok, so its a case of you having a different definition of 'chav' than me. Theres more to being a chav than being lazy, surely?