The need to buy more is very often compensation for the lack of satisfaction or happiness in other aspects of our lives Arturo. Maybe this is where the emphasis should come in - don't criticize, offer something better. We need community, we need love, mutual respect - and, above all, people are never happier than when they are doing something creative - and everybody has creativity in something. We need to learn how to access talents in the community - to relearn the idea that everyone has something to offer.
Some types of expenditure can be regulated - meat and dairy products for example. When I was a kid we ate meat on a Sunday - it was a treat. Now we expect it every day of the week, and for a cheap price. In earlier days butter was a luxury, not now. Maybe we need to allow food prices to rise again, as in earlier days, in order to cut spending power in other areas. In the first half of the 20th Cent. people were spending 30-40% of their income on groceries, now it is around 10% on average (I'm obviously leaving those dependent on food banks out of this equation). There was a time when families would cook for 3-4 days in advance.
As for population control I have no solution - because every possible solution is distastefull, apart from better education. Yet some countries in the Western World have sinking populations, so maybe it would be good to ask how and why ? Instead of that economists are telling us that Germany, Italy and Japan are heading for disaster because of it.