>Side note: My wife is a stay-at-home mom and I've long wished for a disability insurance product that would cover the economic value that she provides, i.e. cover the cost of daycare / after-school care if she couldn't care for the kids. As far as I can tell, there's no such product for people who aren't wage earners.

AD&D (accidental death and disability) is the closest you’ll come. It’s most commonly offered by workplaces I believe, and is not expensive. On the flip side the situations it pays out are pretty narrow.

The only other alternative I know of is life insurance but of course that covers death, not disability.