In a lot of cases it's simple price fixing. If you want to be shocked, compare the prices of frozen potato products (like bagged hash browns and french fries) to the price of potatoes. There's like a 200% premium for simply cutting and flash freezing them. The machines have got to pay for themselves in an hour.

Does it make economic sense? Yes, when you know that there is a frozen potato cartel: https://www.potatopro.com/news/2024/alleged-potato-cartel-ac...

If you want to make your own frozen potato product like this you also need to parboil them. Otherwise the results are acceptable but underwhelming.