I do not think there is a perceptible rise in "conpicuous consumerism" in the upper classes, they don't need to show how rich they are; in the middle classes the rise in consumerism, (hence the consumer society) is related to the advent of the media, from periodicals and journals in the 19th century to the techno media we have today.
This works in 2 ways: by absorbing advertising telling us what we "need", then by not only purchasing the article "needed" but also diplaying you have that article.
Why spend £120,000 on a car which does more or less the same thing as a £500 second hand banger?
One can rationalise -better safety, improved performance, and other supposedly sound reasons for not spending £119,500 on you family. but how valid are these arguments?
Owt else you need to know?