From lived experience, Autism doesn't change over time.
To the outside observer, they may get that impression, but what that really means is the Autistic person is just masking very much to their detriment. Just because they hide it, it doesn't mean it has changed.
The intention is good, but I find this visually lacking, as really the Autism spectrum is more like a wheel shape with each section higher or lower, independent of each other section.
My Autism profile doesn't fit the authors diagrams as they wrongly show it as linear (even though that wasn't their intention).
Cripes, even the normal human fixation on vast oversimplifications probably works that way...