Crowdfunding open source seems like a good idea in general (in fact I could see a platform built around that specifically), but you may be underestimating the amount of money/effort required to build something comparable to Photoshop. So I like the idea in principle, but not in this particular instance.

For what it's worth, I think Sketch is much more user friendly and is $99 one-time. Certainly not OSS, but a better deal than Photoshop for most things, and a much more user-friendly interface than Gimp (though I suppose that's subjective).