GIMP is just hot garbage, speaking from personal experience. All workflows are destructive, the layer workflow is pointy and annoying in so many small and big ways. Performance is bad as well. Small example, take a piece of text and rotate it. After you have rotated it, it no longer is a piece of text it's a slightly blurry piece of pixels. Want to rotate it again? It's now an even more blurry piece of pixels, getting blurrier every time you rotate it. Want to change the text? Start from scratch. Like come on those are the basics and they suck. Personally I don't see it getting a fundamental overhaul, simply because many users are used to the existing workflows and would be upset. I see real competition coming from other projects. But who knows, in general I agree with the sentiment that OSS' endurance is much better.
Personally I don't see it getting a fundamental overhaul
Have you looked at latest release of GIMP? It's just gotten a fundamental overhaul, including support for non-destructive workflows and better text tools. Still has a long way to go obviously and is moving very slowly, but changes are happening.
I don't know whether it will pan out, or whether other major issues will prevent GIMP from ever reaching the status that Blender has gotten to, but GIMP 3 has started shipping some non destructive filters (https://www.gimp.org/release-notes/gimp-3.0.html#non-destruc...) and I (from a distance) understand moving to NDE to be a long term goal of the project
pukes