Well, isn't the Fediverse a large scale open source project? I'd say the difference is that rather that a small company becoming big, what we aim at is more and more small companies becoming interoperable while each of them is still focused on their use case.

No, your Reddit subtitute won't replace Reddit, but it can interplay with more and more other Reddit substitutes, and the connected ensemble may someday replace Reddit.

Is this too idealistic ? 😀