They're around. They cluster, as you might expect. I worked at one a16z-funded startup where probably 1/3 of the engineering department were big spenders. I expect the cluster was a result of the CTO being an extremely big spender, and very loud at broadcasting that fact.

Not exactly huge spenders but I know a lot of people in their early-mid 20s who spend almost all excess income (probably about $70k-120k) on clothes, food, sports tickets, cars, and vacations. And live in nice apartments.