So first I made a fire drill and start a fire, then dig out some clay and fire it into bricks... *some time later* ... then once the UV laser lithography unit is finished, it's time to assemble the 5nm chip fabrication module for the processing units and Voila. That's the whole thing finished!

I jest, but the thing is just because a machine is capable of self replication, that doesn't mean it's any good at making anything other than itself. Organisms are extremely good at making copies of themselves, but they're ultra-optimised for just that. Even the most sophisticated organisms are only able to make a small set of very crude intentional modifications to their environment, if any. We're the only exception.

Self replicators and omni-replicators are very different things.