The intuition is supposed to be that knowledge is on top of something like a mountain. It is easier to climb up a small hill than it is to climb up Mt. Everest. This is because (in the analogy, obviously in real life it's more than just this) Mt. Everest is steeper than the hill your house is on top of.

In other words, the issue with your intuition is that the speed at which you go up the curve is constant, but in the saying, you go up the steeper curve much more slowly than you do the slight curve.

Does that help?