> How much do I offer for this house?

I like the example, but wouldn't it be more parallel to ask "How much have you offered for other houses?" or "How much did your previous house sell for?". The seller would love to know that you are capable of offering more, but you are (properly?) reluctant to give this information.

> But the previous sales are a piece of information about the market that I ought not ignore.

I don't think there is any dispute that this is valuable information to the person doing the hiring. The question is whether it is fair to the person being hired to be asked this question.

Despite the theoretical disadvantage to the business, the current result seems to be that those who are historically disadvantaged will remain disadvantaged, while those who started out with an advantage will be disproportionally rewarded.

Exactly. Good companies understand the value of great employees and I've found these tactics are for companies that penny-pinch and can't/won't budge. No better way to lose out on great talent that to only offer 10% more when other companies realize the value they're getting and offer significantly more.