It's raining. There's one cab. The fare costs 5 dollars. There's two riders. The driver flips a coin. One rider pays $5, and gets a ride. The other has to wait, and then gets a ride.

It's raining. There's one cab. There's surge pricing, so the fare costs $15. There's two riders. One rider can afford to pay $15, and gets a ride. The other has to wait, until the surge dies down, and then pays $5 for a ride.

When there's a shortage of cabs, someone will have to pay with money. Under the lottery system, it's a random rider. Under the price surge system, it's the poorest rider. You haven't actually produced any more value in the third case. The same amount of time is wasted.