You answered your own question. That learning curve, that confusion, you got over it because you're likely more technically minded and appreciate that new software requires learning new skills. Other people find that more frustrating than you and cannot get over it. This is especially true for people that don't use photo editing software all the time

And to be fair to them, GIMP deliberately tries to differentiate itself from Photoshop. It is not at all concerned with helping people make that transition. Some people will make it, some people won't.