What happened is Blender followed a linear development trajectory, constantly adding new features and fixing bugs at a reasonable pace. GIMP, on the other hand,

What happened is Blender followed a linear development trajectory, constantly adding new features and fixing bugs at a reasonable pace. GIMP, on the other hand, adds a handful of features once every year and a half. Marketing was also a factor. Years ago, Blender was similar to how OpenShot is now --- pretty much unknown to the general public, but it shows up in blog posts a lot, and those who use it think it has potential. As time went on and it became more featureful, the news about Blender changed from "This promising project is working on making a modeling suite..." to "This software can replace 3DS Max right now and it's completely free". GIMP's publicity has only gotten worse over the years as it suffers from perceived bit rot and an inability to add requested features over the course of a decade.