Before writing a completely asinine comment like this, you might consider that I, having been paid real American dollars to design this language, might know more than you about the relationship between GATs and HKTs and the design of Rust as a whole. Your comment evinces a total ignorance of the type theoretical issues that actually informed our decision on this issue.
Fortunately, Niko Matsakis blogged about our design discussions at the time. You can read more here and in the linked predecessor posts (at the time we were calling GATs "ATCs") https://smallcultfollowing.com/babysteps/blog/2016/11/04/ass...