By the end of my tenure at McDonald's, we were cooking patties and storing them in steam warmers for up to 30 minutes before tossing them. The same patties were used for regular burgers and Big Macs. We'd create Big Macs as needed by demand, assembling them later.
I don't know the #s, but was told that this change was to reduce product waste.
Grilling equipment and process also changed over this time period, slightly reducing the number of staff needed to run the grill and reduce the likelihood of overcooked (and thus wasted) meat.
I imagine numerous other efficiencies/changes have been made over the decades that would influence the cost to make Big Macs.
There are a lot of ways to make things cheaper. The world has seen startling progress in logistics, organisation, science and tech in the last 30 years. Some of that is applicable to gathering food more cheaply.
I suppose maybe all the gains could have been eaten up (heh heh) by population growth. The underlying equilibrium here isn't static, at any rate. The real price of a hamburger will not be steady.
[0] https://www.ers.usda.gov/data-products/agricultural-producti...
That big mac is at the end of a literally global supply chain. The cost of the tires on the car of the fry cook and the number of temperature sensors one can afford to put in the reefer ship that gets the tomatoes from Argintina all have an impact on the overhead of a big mac. And this is in addition to all the direct process improvements others have mentioned. Heck, the internet has opened up a whole new world of operational efficiency for the farmer that grows the grain that feeds the cattle. He can buy parts for his machines or compare spec sheets for fertilizers from his iphone while sitting in the cab of his tractor that almost drives itself. In 2001 he had to thumb through a catalog or call someone.
1) Self-order kiosks. Definitely reduce costs and required number of workers needed at any time substantially.
2) Scheduling applications. More efficiently schedule workers, trade shifts, etc.
3) Improved warehouse, distribution infrastructure, logistics, coordination software, optimization around deliveries, predicted usage, etc.
Honestly, what they need is a voice AI to take your order in the mobile app.
- more reliable bun-making machines that need a lower ratio of human oversight / bun produced.
- more automation in packaging the meat patties.
What keeps the CPI down is technological progress in other goods, like cars and TVs.