I've been thinking about this thread over the last few weeks, and the above comment.
I'd say that where materialism comes into play is that it's an ontological shift from religious traditions, which sets a new 'framework' in which we understand ourselves and our lives.
For thousands of years people believed they had souls, and were following rules for entry into heaven. That, amongst some earthly concerns that are still present today, defined what living meant to people. Today many people don't have a belief, but the knowledge that existence is fundamentally impermanent and without objective meaning.
So that knowledge sets an entirely new framework in which to approach our lives. If we know that we are impermanent, and that in the grand scheme of things, not much we do really matters, how do we come to terms with and find joy in our lives?
If I'm honest, this is something I grapple with quite a lot. I view the world as essentially unreal, and most things that happen as not really important or meaningful. But I have to live my life despite this knowledge.
So given that situation: how does one thrive and not just give up and become an alcoholic?
I have never imagined nor believed myself to have an eternal soul, and it really doesn't bother me at all.
Why should I care that my existence is of no importance to the universe, or the world, or to the vast majority of people, past, present and future? My life and my actions matter to me, and to my family and friends, in the here and now. What else should I care about, and why?
I don't become an alcoholic because it would hurt the people I care about (including myself). That it won't matter in a hundred years doesn't change the fact that it matters to me right now.
It seems that one of the toxic ideas that religions infect people with is that one's happiness is dependent on eternal life. Ex-theists often seem to really struggle with that one - 'If there's no heaven or hell, then what's the point of anything?' is, to me, a bizarre non-sequitur. Any 'point' is personal and internal; and would be regardless of the existence of eternal life.
The only thing that really changes when you realise your mortality is that you need to recognise and avoid things that can only make you happy after death - ie religions.
Hardship in the here and now to gain happiness in the future is a worthwhile trade. That future happiness might even be purely psychological - such as a feeling of satisfaction when imagining the future pleasure of your great grandchildren.
There really is no point in doing anything that has no prospect of making you happy until after you are dead. But given that happiness can be found in so many ways, that fact doesn't restrict your options much at all.