Well... what if the form of reproduction is a lot more subtle than you would recognize? Meat people producing baby meat people is an outcome of evolution, but robots building more physical robots is the wrong way to think about it. Potentially, its more like github: the designs go out into the world and experience iterative improvement to the software. Sometimes, it forks. Sometimes, it rewrites because it has hit local maxima (aka legacy).

Who is iteratively improving the software?

The human slaves.

>any more than it would be to accelerate evolution amongst animals.

I'm going to assume you've never been to a farm and seen huge fat chickens. Yes, selective breeding is an accelerated evolution to traits we want.

And it is not our best interests to make an evolving robot,

But that not the question, the question is, can it be done. And if that answer is yes, it will be done.

In a way they could reproduce. They might just need to convince a human to handle the physical part - assembling a new host computer, but that could be just about giving the human the right incentives (maybe $ or knowledge).