The theoretical reasoning of philosophy and religion created dualism, which split the world into mind and matter. This is not just a cosmological distinction: in everyday human life, dualism is the unseen foundation of thought, and it has caused the major problems we face today.
First, we see the rest of the world as apart from ourselves: as essentially inert stuff that can be manipulated without consequences. This restricted view has had obvious negative effects on the environment. Second, we have come to view ourselves -- who we "really are" -- as minds, and in particular as theorizing, rational decision-makers. This also has terrible effects on us, emotionally and socially, as we are cut off from experiences and choices that do not involve maximizing logical abstractions.
In all ages, people feel deficiency, but they think of it differently, and experience different kinds it. In our age, because we view ourselves as mental, our deficiencies are also in this mode. It may not immediately seem like this, because on the surface, we want for social status and material goods (through money). But why do we want these things? We create, in our minds, ideas of what we should have, and we strive towards them. What we find in life, however, is that there is no limit to what we will want, and we are never satisfied. First-world ennui is the result -- but it is only an indicator of deeper problems.
Why does consumerism not work? Because really we are not drawn to particular material goods, but to a vision of ourselves once we have them. And what is that vision? We want, of course, to imagine our desires fulfilled. But with that comes a corollary that is more to the point: we want to see ourselves without desires at all; just being. With that, we imagine an end to our need for analysis: we want to simply enjoy things -- to finally experience emotions other than acquisitive desire.
This is the haunting mirage of consumer capitalism. But it is also the mirage of all major (axial) religions: Buddhism seeks the elimination of desire, Christianity wants it only for ideal things (god), while Greek philosophy elevates rational existence. All our religions today are otherworldly, seeking an escape from deprivation in perfect states of pure mind. And whether we pursue our material desires in an attempt to satisfy them, or in an attempt to renounce them, the problem is the same: we are locked into seeking an abstract ideal that finally is free from desire and analysis. Neither approach will work to bring about this result.
The physical world, or our relation to it, is paradoxically at the heart of fulfilling a non-physical ideal. To gain control of the physical world, we create abstractions of it: these free us from any concerns about the world's inherent value; allow efficient decision-making; and create a target for renunciation. Thus, the modern method for striving from deficiency is centered on manipulation of abstractions. What this produces for us is a depressive, dark view of physical existence: it is only a cypher for theoretical goals we have not yet reached. What lies behind them -- the real physical stuff -- is just in the way.
Meanwhile, what we hope for is eventual non-manipulation, non-desire, and non-physicality. If we could succeed, the only thing left would be fulfilled goals and a memory of the means we used. This, we think, would be the pure us. Unfortunately, we have defined ourselves as analytical agents. And what is an analytical agent if there are no goals left to it; no decisions; no problems? This is the essential nihilism of mind-matter dualism: we identify ourselves as half of the equation, and seek thr a dissolution of our opposite; but that would disolve our own self-concept as well. This applies not just to some afterlife, but how we live now: how we conceive of, and experience, our existence.