It ain't the poor, it's those who have the biggest barrier to going anywhere else who will get slugged, and slugged hard. That segment of the market will pay loads. Flights from New Zealand to the Pacific Islands for Christmas are legendary. Pacific islanders in NZ do not constitute the rich. You don't care whether you go to the Solomon Islands for christmas or just after? Much cheaper. But what if there are empty seats on the plane you could have sold to regular holiday makers at regular prices? Airline ticketing is one example of this - we can take the principle to so many places! Uber can do it! Anywhere the vendor has market power against a market segment they (yes me and you as vendors) want to exploit it.

When the vendor know what's in your hand, your "I could walk" bluff is called and you get smashed. Every business including yours and mine wants to charge every single customer as much as they will possibly pay. Capture consumer surplus. Surveillance capitalism can help here.