Most of the research shows that beyond a certain amount necessary to be secure, more money doesn't make us any happier. Can't remember the exact figure for the UK.
BTW, if "it is part of human nature never to be satisfied" that doesn't necessarily imply that we should all naturally aspire to more in a material or financial sense. That's one aspect of it which, as a kind of envy and sense of inadequacy, is exploited by consumer capitalism, media, political parties all promising 'more' that they can't possibly deliver. But we don't have to be that way...
There's good aspects of that drive too though - not being satisfied with poverty, injustice and the world as it is. Being creative, scientific discovery etc. But that implies a kind of satisfaction with yourself and not worry about how others might see you, that allows you to deal with important things that are genuinely unsatisfactory...