You are robing Peter to pay Paul. You get your money up front. It looks like you’re making money hand-over-fist, but you don’t realize that sooner or later, you’re going to have to pay the piper.
The reason the IRS allows a deduction of $0.54 per mile is not because they want you to pay less tax; they do it because statistics show that it actually costs that much to drive a car in the long run. There might be some wiggle-room there, but if someone came to me and said, “Give me $0.45 per mile and I will cover all your driving costs, soup-to-nuts”, I would jump at it. I have spent $0.19 per mile for maintenance on my two cars over the last two years. If I add depreciation, I’m up to $0.32 per mile before gasoline or insurance, which easily boost me over $0.45.
Try this experiment: at the end of every week, look at your total mileage, both Uber and personal. Set aside $0.50 per mile in a special savings account (or a cookie jar). Whenever you have a car related expense, be it gas, insurance, tires, collision deductible, pay for that from the cookie jar. You’ll be surprised how fast that account grows in value. At the end of four years, you might have as much as $15k in the cookie jar. But it all comes crashing down when you have to buy a new car and there is not enough money in the cookie jar to buy one.
Taking all this into account, I estimate that you’re making less $8.00 per hour. If you’re having fun: enjoy.