I agree, it is a natural thing to adjust for supply and demand but imagine if there was no backlash on this and stores like Walmart or Costco decided to implement a similar AI managed pricing system. You could see one price when in your cart but see another by the time you reached check out. It would be quite a show as people flipped out at the cashiers.
The thing Wendy's is missing here when trying to adopt an "Uber like" pricing schedule is, the Uber drivers do see some of that in a slight pay increase. It is not proportional though which is still unfair but the drivers do see some of the increased price customers pay during peak time. Wendy's has been absolutely silent on the employees seeing any pay increase during peak time.