The trick is to get the right balance for your von Neumann probes such that they survive long enough to propagate (hazard remediation mostly) while also not bottlenecking on a resource. Iirc you can harvest so much so fast that it's easy to be set for the foreseeable future. I would occasionally just stop mass/wire production to get my fleet going strong and it would take a long time before I needed to restart it. Meanwhile trust stacks up and probes get better.