It's really an observation that different abilities [...] will "naturally" lead to inequality

Then yes, I agree with that.

I treat value as subjective

Me too. What I wrote should be regarded as shorthand for something like this: "net value to society, which of course different people will assess in different ways; I have mine, Eli has his, Lumifer has his or hers, etc. I expect these different assessments to be similar enough that it isn't worth filling this discussion with metaethical digressions about how different people have different values". Perhaps there's some way I could have put it that wouldn't have given the impression I was talking about magical Objective Real Moral Value without filling the thread with metaethical digressions, but I didn't happen to spot one :-).

For the same reason I find "value to society" a suspect concept.

I'm not sure I understand this. It looks to me as if the following two questions are basically independent: (1) Is there one true way of assessing value, that isn't dependent on any particular valuer's values? (2) Is there, for typical ways of assessing value, a meaningful way to aggregate costs and benefits to lots of different people into an overall "value to society"? I answer "almost certainly no" to #1 but "yes, at least roughly" to #2.

I generally don't up- or down-vote comments in threads in which I participate.

Useful to know. (Neither do I, FWIW.)