It's actually the opposite of disproportionate... It's proportionate. Firstly, these aren't wage jobs, so you're not entitled to a definite hourly yield. Secondly, if they lower their prices then they lower their returns too because it's a fixed commission. Thirdly, it's possible that a lowered price results in improved profits, if the frequency of rides go up. I've seen nearly no change in hourly profits despite lowered prices.

And I do think Uber is very sketchily overestimating their driver performance in their recruitment efforts. And I think the extended line of credit for car purchases was dumb, but I didn't take it.

Also your analysis has this problem -- by your argument, drivers who are more willing to accept a slimmer margin are "more powerful" although those are exactly the "economically disenfranchised" drivers.