GIMP is GNU Image Manipulation Program. GNU is Not Unix - free operating system.
GIMP is there not to replace Adobe. It is there to provide free, as in freedom, software for image manipulations. That means, you can modify it, you can see how it runs, you can learn from it, you can make your extensions, you can sell it, profit on it, license is basically yours, as long as you provide same freedom to others.
Adobe Photoshop is like Guantanamo prison -- there is no way you can re-sell it, modify it, re-compile it, see how it works, share to others for free.

You caused me to escape my enjoyable eww environment, just to answer you back:

• - of course ImageMagick has dependencies
• - dependency failure is not failure of ImageMagick, it is yours, just yours,
• - try to compile ANY software without dependencies, it will fail, that is why it is named "dependency"
• - I have compiled 500+ packages for GNU/Linux and running on the whole system - self-compiled
• - ImageMagic included and working very well, doing magic with it, I guess that is why they named it so