Going by pure economic theory "dynamic pricing" actually benefits both buyers and sellers in a marketplace. There are plenty of cases where it makes sense – lunch menus at restaurants, grocery store coupons, retail bargain bins, dollar menus, happy hour deals, senior/youth/student discounts, even surge pricing in Uber & Lyft. Of course like with every aspect of economics how something is implemented matters a lot more than how it sounds on paper. Especially in the case of rideshare/food delivery, where the middleman has all the data and makes all the decisions.
Yes. This is why getting an Uber is merely expensive instead of impossible on rainy days or on New Year's Eve.
Dynamic pricing makes it possible for both riders and drivers to respond to changes in supply and demand. If prices were static, many drivers would prefer to go to a New Year's Eve celebration themselves than work, but when it becomes their biggest paying shift of the year, they're a lot more willing to do it. Riders have to pay a bigger price if they want a ride at peak times, but it's still possible to get one when they really have a strong preference to.
Wouldn't perfect individualised dynamic pricing mean that the seller (Uber in this case) would get to capture the entire consumer surplus? Is that good?
Yes but also that some people would be getting a service that they otherwise wouldn’t be able to afford. But there’s little/no incentive for a pure seller to do that, although for a marketplace like Uber there is more possibility for that, in order to maintain liquidity on the other side of the transaction. I listened to an interview where Uber CEO Dara K note there is always an incentive pool, and based on the market it is either riders or drivers who are getting the incentive money at any given time.