Well, you've started from a tautology. A great many profound truths eventually terminate in tautology though, so it is reasonable for what you've said to make sense.

Actually, it is interesting how truths come to tautology.

Are you curious about that? I don't know. I think it's interesting at least. And kind of exciting. When a narrative (if that is the right word?) reaches truth, it does so by realizing it. It realizes it (as opposed to, say, creating it), because the truth was there all along. With people, it is always like this. IF you are willing to say that the universe itself is engaged in this kind of narrative (because you are an idealist), then you can make sense of "no one thing comes from no one thing" (which is true) through the clarification "all things come from what is in itself all things." "in itself" serves as a placeholder for that which must be developed, and allows your truth to be lived or realized temporally. It allows you to retain the idea that all things came from one thing, but that the one thing is in itself everything. Besides, one you claim every thing into a conceptual set "everything" then you've implicitly made it one thing, and that one thing is infinite, since infinity just means none else than the concept of everything for which there is nothing beyond.

Just my take on it.

Also, it is reasonable if you say that nothing could come from one thing on the grounds that just one thing couldn't exist without being many things. If you try to think about one thing, you'll automatically oppose it to what it is not, namely, nothing, so the one thing isn't really everything, at least conceptually. Conceptual one undifferentiated thing is something no one can be conscious of because there is nothing there to be conscious of. But you know, a lot of people mistake that what seems like one thing as the actual one thing in concept, and so people will make the mistake of trying to UNdifferentiate things in order to unify them, when SINCE it is articulation and development which actually leads toward the realization of truth, which terminates in tautology, they are trying to move backwards. For example, people will try to undifferentiate themselves or others, which explains a number of unhealthy choices people can make ... causing them all sorts of strife ...

Isn't it cool though? Idealism, man. I'm really trying to sell you on it. It's a good time. Ra ra!