Agreed - and that was sort of my point about Uber taking advantage of regulation, though I didn't phrase it well. The artificial scarcity of taxi medallions meant that demand outstripped supply outside of Manhattan. Now they're finally, slowly, fixing that.
Even cabs (green and yellow use the same fare structure) are priced way out of line with what the gypsy cabs were negotiating in many parts of the outer boros. UberX is another 30+% again on top of that.
It looks to me like uber's biggest market in NYC is not people who live in outer boros and would otherwise have hailed a green or gypsy cab but people who would otherwise have taken a pre-arranged black car because hailing a cab is for the proles. That market isn't nothing, but it's far from the whole thing.
Up until the beginning of the year, 90% of the time you'll be hailing a gypsy cab. The only time you'd get a yellow when leaving the BX was at shift change which is around 5pm/5am for a lot of them. Not that there's anything wrong with a gypsy cab, but you're not supposed to hail them, which ties into a lot of the problems Uber appears to be facing in NYC.
I will say a lot has changed with the introduction of the Boro cabs (green cabs). I don't remember exactly when they were introduced, but getting a cab is considerably easier now.
So, while I agree with what you are saying, I think it's a little Manhattan-centric.