I've been trying to get to the source of where this raised bed nonsense started and I think I may have found it:
Mel tells us he's not a horticulturalist, he's a civil engineer - he can build a box. Unfortunately for us he's also either a well-intentioned fool or a snake oil salesman. Going by the claims he makes I'd suggest the latter: he says compared with traditional methods his system uses 90% less water, 95% less seeds, will solve the world's hunger problems...no doubt it'll also give me a full head of hair and make me irresistible to women. He doesn't substantiate these claims, no doubt I'm supposed to buy the books and DVDs to find out - he must be one wealthy snake oil salesman judging by the amount he's managed to shift.
So you don't have to dig up your lawn - actually Mel that's exactly what you should be doing, even Michelle Obama's managed to figure that out. The soil is already there! You don't have to move it from A to B! You don't need to build boxes to put it in! This is not civil engineering!
Good grief Charlie Brown. Only in America.