Apple laptops cannot have their video card upgrades. They have never manufactured a laptop that allowed you to upgrade the video card and chances are they never will.
On the PC side, I would say at least 98% of current PC laptops do not allow you to upgrade the video card. Those very, very few that do will easy cost over $1,500+ and they must be gaming laptops. For example, Falcon North West does have one or two models that allows you to upgrade the video card, but they cost nearly the same as a down payment on a car.