If the central protection from machines evolving to eclipse humanity is the lack of a means of reproduction, we might well be fucked.
When I first read this I thought about #reprap, and mechanical machines that are capable of reproduction. This was a little spooky, but it's pretty indirect, and there's all sorts of wrinkles (most repraps can't reproduce their electronics).
But then I thought about software. If we think about software as machines (and I imagine the author would have if it had existed when he wrote this) then we've recently crossed this line with gusto, perhaps first with the general availability of Github's autopilot and then accelerated from there with several products which are fully capable of allowing software to reproduce and mutate without human intervention.
https://en.wikipedia.org/wiki/Darwin_among_the_Machines