Blender has the advantage of having been a commercial product that went open source, thus many people on the initial core team cared about stuff that other projects don't, plus they already had an installed base.
You don't see the same success with Gimp, Krita,...
Have you actually tried that "commercial Blender product"? Before open-sourcing it, Blender 2.2x was incredibly user hostile and barebones in terms of features. For example, in mesh edit mode you could only work on points - no edge or face selection. It was very primitive, both in its UI (which was inscrutable) and its rendering capabilities (e.g. except for spotlights, lights did not cast shadows - and spotlights could only do shadowmaps). Very basic usability features were added pretty much as soon as the project was opensourced.
Remember that Blender was opensourced was because it failed commercially. Its commercial background is completely irrelevant to its success - which took years to achieve and most 3D artists for more than a decade saw it as a toy (undeservedly IMO because even by 2.44-or-so it became very capable, but the UI despite its massive improvements was still very undiscoverable and alien for most users).
You can download "Blender Publisher 2.25" from blender's own site which was the last commercial release to check it..
You don't see the same success with Gimp, Krita,...