Those don't show the difference in the thickness of the old units either. Half of the problem with the old designs were that the technology of the screens, processor/hard drive, were much thicker....similar to the thickness of a current day laptop at the thinnest. This made them want to put grips or handles on it so people wouldn't worry as much about dropping them.
Now, due to the popularity of smartphones and the thinner screens/devices, they push the "grips" on to the case manufacturers. It makes sense that Apple let things evolve this way.... For the record, as a former customer of Apple....I probably won't buy anything else from them if I can help it.