I think it's also worth noting that OSS did not 'make' Blender initially - it was a closed-source application. It's a resounding OSS success these days, but had already been 'productised' before the the release of the source.

Blender was a commercial product, whose main users kept supporting after it went open source.

And early Blender sucked ass compared to today. While it starting as a commercial product might have helped at start, right now it's no longer the case.

Because the commercial partners cared enough to keep putting the money to further develop it.

Blender always had a professional userbase around it, unlike the Photoshop wannabe competition.

Krita is great but has a different use case than gimp.

Krita is nothing like GIMP

In a good way. I’ve certainly completely replaced Gimp with Krita for my uses.

To an extent, yes. But as someone who likes to draw and not edit pictures, they fill a similar niche.

I mean I heard people use Blender as a Gimp replacement. Because it can edit huge number of files in a batch.

People will use anything instead of gimp to be honest. Haven't tried it in a while but everytime I did in the past I can't help but question if it's developers actually use their own software.

Not me. Whenever I try alternatives, I can't help but question if people who use GIMP alternatives actually tried reading the GIMP manual.

If you need the manual it most probably means the UI needs improvement.

Only under the assumption they're designed for usage without the manual. I understand most things are but they definitely don't have to be. GIMP unfortunately may not be particularly explicit about this but having all users read the manual feels very much intended.