Supply and demand. What the market will bear.
I sold my 5er a year ago last May and started looking to downsize to an F150. Lack of inventory on lots led me to decide to order exactly what I wanted. First contact with local dealer he said there was a $10,000 premium over sticker. Told him no thanks. Few days later got an email saying $5,000 over sticker. No thanks. Then an email saying no premium. Then I was at least willing to talk. Ended up ordering for about $2,500 under sticker. Far higher than I was accustom to. But my F350 I was selling was valued for far more than it had been a year earlier. So I paid more than expected for his and got more than expected for mine.