Don't know why people hating on GIMP.. maybe it's not exact replacement for photoshop.. but I've used it for product photo touch-up work and it gets the job done. Which is great job for free
It's unfortunate that their funding situation is so dire. It's a project that could use a cash injection like Blender got. Blender went from having a terrible UI to winning awards.
Blender was also the forerunner in having a kickstarter-like scheme to raise enough money to make it opensource.
There's an interesting interview between Ton Roosendaal and Blender Guru about the history. https://www.youtube.com/watch?v=qJEWOTZnFeg
The Blender guys were also a lot less hostile towards people trying to make improvements to stuff like UX.
One of the things that GIMP also desperately needs is a name change, while Blender is an odd choice it at least doesn't conjur up sexual images.