The issue isn't consumer demand but rather dealer demand. US franchise new car dealers live and die by inventory turn rates. Due to the way that floorplan financing works they can't afford to have a car sit on the lot for months. Most customers who would prefer a manual transmission will take an automatic for a good price, but customers who want an automatic won't take a manual at any price. Thus except for a few sports cars, dealers are almost never willing to order manuals from the manufacturer.

In some other countries the new car sales system is a little different with more consumers wanting to custom order the car they want, then wait for it to be built. In the US, many mainstream brands won't even take custom orders anymore.