Evolution vs creationism... why is this even being debated? Because people are indoctrinated from a young age. In their world, you can't possibly be Christian if you don't believe in a six literal day creation involving only two people who didn't even have a daughter, so there's that.
1) There are not "millions of these;" the first species pictured represents the hypothesized, now extinct, and yet to be discovered 'missing link' connecting human evolution's beginning to the family of creatures preceding it--not a chimpanzee. 2) The reason there aren't millions of the middle species is because they also represent now-extinct human ancestors, i.e. Homo heidelbergensis. 3) All of the species behind the modern human shown represent currently extinct, ancient human ancestors.