The scaled down rectangle should be narrower; it's not scaled in this diagram, it's squished.
(Yes I know you can 'scale' objects on one axis but that's usually not how it's taught on an introductory level. Standard scaling assumes object similarity, which is not present in the diagram's 'scaled' rectangle.)
Scaling in 2D has 2 parameters, X and Y, in the example X was at 1 while Y was below 1.
You are referring to a subset of scaling transformation where X = Y and the aspect ratio is kept.
Yes, and introductory geometry courses teach students how to do uniform scaling far before they teach them axis-based because it's better illustrative of the concepts of similarity and congruence
Ackchuawually, this example depicts a squish and a translation. A true scaling would have the scaling being done in place, resulting in an overlayed and smaller rectangle.