The haggling involved in car buying is a choice. Over the years various sellers have used “no haggling” as a selling point, Saturn for instance. But I can walk into any dealership and choose to pay the listed price without haggling.
They have multiple avenues for haggling beyond price. Leveraging loan terms or penalizing you for cash, insisting on addons like 'safer' blinking tail lights that they auto-install on every car, the creativity never ends.