Those aren’t equal. I “haggle” for burgers by choosing the restaurant that will serve me a burger I will be satisfied with for a price I will not be dissatisfied with. For me that’s a local chain that’s fairly consistent and fairly good for more than I will pay at McDonald’s for the same type of dish, but less than half the price of a “better” burger somewhere else. This “haggling” happens before I even enter the store, and influences my choice of stores, but at the end of the day we’re talking about dollars for burgers and fries.

Prospective employer-employee negotiations are an exchange of time into work product in exchange for dollars and benefits measurable in dollars. Time is more valuable than dollars, and I want a good price for it, commiserate with what I think my time is worth, and informed by what I’ve been able to receive in compensation for it in the past because I’m taking a risk by taking the job, including leaving my old job. The employer is also taking a risk, onboarding new employees is costly in both time and money, and they want some idea that you will be worth the money they spent because they expect to make more money than they put into you, so if they can get away with paying you less, of course they will. That’s what makes this a market. I’d rather have a bad lunch I paid too much for and a good employer than a good lunch for a good price and a an employer that doesn’t pay me a compensation I am satisfied with.

I've never been equated to a burger before. That's novel.

If the burger would cost $100k plus RSUs, yes I probably would negotiate for it.

all expensive items in US have no fixed price and vary based on negotiation outcomes: car, housing. Negotiation is actually a sign of a healthy and competitive market, because there is always a spectrum of talent available, and demand for such talent.

only monopolies can set fixed prices and it leads to inefficiencies