When something I made is sold at a company, used raw materials are rebought, but then left over is the wealth I created. A portion goes to me in wages, a portion is mailed off in dividend checks to the heir who is expropriating my surplus time. It matters because the heir is expropriating surplus labor time from me, and all the wealth I create in this time. That is why it matters.
Irrespective of that you are assuming happiness is just associated to absolute monetary wealth - which I disagree with. If basic resources and needs are catered for and the rest is spent on luxury goods or extravagant lifestyles - how would I care? If you want to still play that game, just travel and ask yourself what a person living in India/Bangladesh/Laos would say about your first world problems. Being born into a wealthy society is the most important differentiator for wealth - and I assume you are totally ok with the luck you had there!?
[1] I'm using "everyone" metaphorically here. No system is going to have literally no one who falls through the cracks.