That's a good insight into the sales tactics. I read once that one major strategy is to create urgency in the buyer. "Buy now! Interest rates are about to go up!" "Sale! Prices are unusually low!" To sell someone something they don't need, this kind of strategy is needed. You must convince the buyer that they do need the product. Unfortunately our culture is awash in this kind of crap because so much of our GDP is driven by "consumer spending."
But what other commenters are saying is true. You can't really "hold on" to your money. Cash is depreciating in value all the time. So you probably do want to spend it – by buying assets. Ideally appreciating assets, such as stock or residential property, and not a 100% depreciating asset like a car or a boat.
MMM basically does advocate giving your money to corporations. Mustachianism is anti-consumerist for many reasons, but it's definitely not anti-capitalist. Indeed, it is profoundly capitalist, since the goal is to own as much capital as possible and to eschew purchases that do not give you capital. Most of the world's wealth is either generated by corporations or by natural resources. The only way to acquire wealth if you aren't already wealthy is therefore to buy part of the corporations (or the natural resources, if you're into agriculture). Honestly, I was very hesitant about buying stocks until I made this realization and accepted this as inevitable.