Von Neumann machines are fully automated, which is still too hard to do. A seed factory allows some human labor where needed. It just turns the output into self-expansion rather than cars or washing machines like a regular factory.

Also Von Neumann machines make an exact copy of themselves. That's "direct replication". They have to start with a full set of machines needed. Seed factories work like plant seeds. They start with the minimum set of equipment to allow growth, then eventually can make new starter sets. But the new starter sets are not identical to the grown factories.

Social progress is being held back by fear. Rural white people are afraid of losing their position on top of the "natural order of things" (their view, not mine). Having grown up in New York City in an immigrant family, I'm not afraid of people who are different than me. They are just people.

But if everyone is well enough off through productive means, you don't have to be afraid of losing out.