I always see people say this but I don't know how they were subsidizing rides. I was an early Uber driver when I was in grad school and I received roughly 2/3rd

I always see people say this but I don't know how they were subsidizing rides. I was an early Uber driver when I was in grad school and I received roughly 2/3rds of what riders paid. Was Uber's third take too low? I would also receive a lower fare when the rider used a coupon or had a promotion. It always seemed more like I was subsidizing the rides rather than Uber.