@DavoMagic You have to consider the franchise model. Remember, Dominos Corporate get a % commission of turnover. That's why they do these cheap pizzas, the profitability of the franchisee in secondary to the incentive to drive sales. I doubt the franchisees make anything on a $5 pizza, especially when you consider most independent pizza shops operate well over $10 and don't pay royalties.
On a side note my local kebab shop has gone from $10 to 13.5 for a lamb over last couple of years. Its not going to wages or the owners, its going to the delivery platforms that take 30%.