Yeah thinking back even further, it really began (no surprise) with the Boomer Consoomers when they were growing up in the 50's/60's. They were the first generation to grow up with mass-media and advertising targeted directly at them. Before that ads were largely targeted towards housewives (e.g. the original "soap" operas on radio) and more commonly touted the virtues/benefits of a better product, rather than buying crap you don't need just for the sake of buying.
I'd say what spawned consooming was the perfect combination of a large, young, impulsive & impressionable demographic (boomers as children), strong economy with more discretionary household spending, development of low-cost production (plastic), all magnified by the universal reach of a visual medium (tv).
So yeah, we can blame the boomers for starting it... each generation since then kicks it up a notch, and the internet gave it steroids. Like you said it's evolved into hyper-consooming at this point.