While I have not looked at store eye tracking data, that from web pages will tell you the fold is a real issue. With the fold on a web page you have to scroll

While I have not looked at store eye tracking data, that from web pages will tell you the fold is a real issue. With the fold on a web page you have to scroll and keep scrolling for something to come into the visible space. For shelves you can look at a wall and see, even if not at the focal point, other items. In my personal experience, it's much easier to spot and look at the alternatives on store shelves than it is to navigate sites and look for comparable things.