i don't really see agnosticism as a step toward atheism per se, but it is for some people.
agnosticism is really it's own thing. it says 'I don't know whether or not god exists." it rests comfortably in uncertainty.
atheism is more assured. it says "there is no god" just as theism says that there is. both are certain of their position.
for me, i'm not exactly comfortable with either title.
first, i am not uncertain about what i believe in. to give a more accurate but not precise definition, it would be theism. but, it's not precise because of my buddhist studies/practices.
in the school of buddhism in which i practice, the idea is that there is Nothingness. This has attributes of divinity, creative potential, etc, but is not worshipped as a God. it is simply the place from which everything arises and returns. It is the ultimate consciousness, and when we achieve enlightenment, we are existing from this place of NoThingNess. there are no divisions between I and You for example. because I and You are really NoThingNess.
So this is understood to be Atheist.
To me, this NoThingNess is atheist. but it has divine attributes, so it looks a lot like God. in a way, it is.
To me, it's just an issue of language. Atheistic buddhists would say that it is nothingness. A theist of nearly any sort would say that it is God.
so for me, I am comfortable saying it is not god or nothing and i am comfortable calling it god. either way, i am fine.
thus, it's not really agnostic either. agnostic says "i don't know what exists." i believe that nothingness/god exists, and that it is a nothing-something. it is a something-nothing. so i do have a belief.
and that belief--depending upon how someone else frames it--is either theist or atheist. and i don't know what to call it myself, or even care to call it anything really, and so that is "sort of" agnostic.
so, atheist, theist, and agnostic are not precise, but they can be accurate depending upon context.