Most of those people, who are happy with money possible to earn by Uber - have never ever made a precise calculations. And once they finally do - usually they just quit. Here in my country Uber have set the ride prices crazy CRAZY LOW:
€0.59 start fee + €0.33 /km + €0.09 /minute.
Their (uber's) commission is 25%, and driver also must pay VAT from that commission 21%, which makes total 30.25% deducted instantly from every ride payment. Now imagine, if I drive to pick up my rider 4km, and he rides only ~2km, he still payes the minimum, which is €1.50 . From that for driver is left €1.04. To drive 4+2 km, if i deduct all all expenses associated with my 6km drive ( fuel, oil, tires, ensurance, carwash, taxes ete etc ) , what is left is around maybe €0.25. Sometimes even less. And this is for a small car Toyota Auris 1.8L HYBRID. YES, Hybrid. Many with larger cars have much higher expenses.

That all comes to the result - to buy a cup of cheapest cup of coffee in local gas station, I must complete 4-5 such 4+2 km rides ( five?!) Which would usually take 1.5-2 hours.

So, how do you like this - working 2+ hours to buy a cup o coffee in the local gas station ???

That what is UBER here...