In the US, people don't really haggle every day. It's not part of the culture. This stands in stark contrast to the experience of buying a car, which is something people are never going to do frequently enough to build up haggling skills. So it's really context dependent.

In a culture where people haggle constantly (or at least more frequently), then a larger portion of people will have the relevant skill set to navigate these waters. I guess you could "solve" it by building haggling into the culture, but you could also "solve" it by forcing car dealerships to normalize with the way that most other average purchases work.