Issue is that haggling is actually legal in many countries.

So at the cashier they will make you an offer, which, if you pay, accept.

Now with technical support making individual offers becomes pretty easy and effordless on their end, but if you are in a hurry you don't have that technical support to make a counter offer that effordless... So the shopper is at an disadvantage. Either way, your reaction, wherever you buy or not will train the AI of the store to extract the maximum amount of money of the broad customer base. If some people are priced out of living, they probably don't care.