Probably the same reason goldfish like shiny things and my dogs fight over the same damn chew toy even though they have five different ones. As soon as humans stopped being vagabonds and learned how to plant, we learned that it's better to have more than less. Soon, more chickens and millwheels became more silver and gold. Now we have massive token economies and monetary wealth that defines us. I don't neccessarily wish it would change. I gave up chasing fancy cars a long time ago. I take pride in watching my retirement savings stack up, driving my crappy paid-off car, and knowing that sooner than most I will be out of the rat race.