Exatcly. And thats the case is many other countries.

Same here, and same for many of my friends that I've talked about this with.

Because Uber's wages are low.

Because it is the baseline for yellow cabs and black cars in the US

From my perspective, a valuable service that Uber provides me is to get rid of the hassle and annoyance of tipping.

Of course, for this to be done well they need to pay the drivers enough that tipping is not necessary.