Thanks!
wboggs, Greg is right--the meal and the plating is normal for me. But it's a good question.
Plating like this pre-dates the Food Network by many years. I (and others) plated similarly more than twenty years ago, but you're correct that, in the scheme of things, it is a relatively recent invention. (Some might call it a conceit.)
I do not recall who, if anyone, was credited for the style, and I don't doubt that there were those then (as well as those now) who might plate this way simply to create an illusion of quantity. That's not my motivation nor that of other chefs I know but I will concede that it is helpful when it comes to portrioning the smaller-quantity items on a plate--things like condiments, edible garnishes, smaller sides, etc. For instance, the tomato-shallot-caper jam--just a dollop on one end of one tyropita--would have looked minuscule if alone, worse if relegated to a little side cup or dish. One would have had to increase the quantity just to make it look good. Likewise, the button mushrooms (a serving of just 3 or 4 per plate) would be lost in a side dish (though they'd work if off by themselves on a plate). So, it's a visual thing with an eye to cost effectiveness.
Plating for visual height can make a plate arresting. But it is not always appropriate and I don't always do it. An example: I enjoy pulled pork dinners with sides of crisp coleslaw, spicy beans, turnip greens and cornbread. I think all these items work well together taste-wise, but how could I possibly plate for height in a way that made sense and looked good? I couldn't. Conversely, for a plate I did not too long ago, height made the plate look best and made perfect sense to me. The meal was of spit-roasted poussins (small chickens), served halved, one half per plate, grilled polenta rounds, grilled fingerling potatoes and grilled asparagus. The sauce was roasted garlic jus. I grilled the asparagus whole but halved them crosswise for plating, putting the halves (4) off-center on an oval plate crossing each other. This gave me a little height and I placed three grilled polents rounds on the asparagus, leaning on it and slightly overlapping wach other. Then I placed the poussin half--the leg end--on the polenta, the breast end was on the plate. This not only gave me more height, but the angle of the poussin (breast lower than the leg end) allowed juices to flow toward the breast, keeping it moister. The fingelings (which I'd halved lengthwise for grilling) were interspersed with the asparagus tips on the plate next to the breast. I drizzled a little sauce on the leg end and it, combined with the natural juices dripping from the underside of the leg end, moistened the polenta nicely. The rest of the sauce I served in ramekins on the side. So, the motivation can be one of cohesiveness of flavors and textures, complements and interesting contrasts, and that is most often my motivation for planning a meal and plating this way.
Hope this makes sense.