i think this is unfair. I am not a big fan of uber, but uber already provides value, has a solid service and penetrates international markest (not native, is this...right? sounds kinda wrong imho). Autonomous driving complements their original target (taxis) and makes it possible conquer new markets. I get what your idea is, but i think it's wrong because what they do makes sense and they are actually building (and delivering!) stuff.

They might gamble too high and loose big time, but i wouldn't call it a ponzi scheme.