Three things I learned during 4+ years at Uber
Michael Pao

It seems to me that a marketplace for labor (drivers in the case of Uber) is quite different than a retailer like Amazon. If Amazon sells out of a product, they just show “Sold Out”. A higher bid price will not cause another unit to suddenly become available.

On the other hand, a labor marketplace like Uber is more like the stock market where raising the bid for shares of a stock or more drivers will almost instantly attracts new sellers.