We want highly detailed miniatures, partly for ourselves but there is some element of competition and comparison with others. It's the same for cars and make up and practically everything else. ...
If everyone got out of bed tomorrow and simply chose not to wear make up or to buy the fanciest car, then I think prices would drop, people would readjust what they thought was pretty, etc.
I think you're right that there's an element of competition here, but that's only part of the story. The desire for more and more stuff is arguably unhealthy, even if it doesn't involve competition.
Unfortunately, what you're asking for relies on human beings having a stronger willpower and sense of self than what most can actually achieve.
I don't think any of this is 'hard-wired' into human nature. We're all shaped by the societies in which we grow up - and which often encourage consumption, even to the point of competition and greed.
Perhaps this is what you meant and you're talking about the willpower to resist this social condition, in which case I agree. But, if you mean that behaviour we see around us is 'natural' or inevitable, then I disagree.