Kodak simply makes sheet film in big rolls. It doesn't matter the size of the sheet, provided the request meets their minimum order quantity for that size, so it justifies the cut and packaging setup charge. Since 4x5 is by far the most popular size, they routinely offer that. With 8x10, I think the minimum order is something like 70 or 80 boxes, so there might be only a few cuts of that per year for certain dealers or pre-order pools regarding color film, and even less often for 5x7 cuts. Black and white sheet film is more in demand, so liekly cut more frequently.
This is completely unrelated to 120 roll films or 35mm films, which each involve their own coating on different bases than sheet film.
Printing color film is still relatively affordable unless an exotic process is involved. My own capacity is up to 30X40 inch prints; but even a huge 30 or 40 inch wide roll of Fuji RA4 paper generally costs less than a 50 sheet box of 16X20 or 20X24 FB black and white paper these days.