What he is describing is the same thing I experienced as a first and only (for 25 years) wife. I cooked, cared for animals, cared for children, nursed the babies, anwered the business phone, worked in the garden. In the summer I was too exhausted for intimacy by the time the chores were done and the kids were in bed. I remember very distinctly feeling that I could have more QUALITY time with my husband if someone else was here to help....and she might also get more QUALITY time than she would as an only wife.
I was never wanting less of my husband, but rather thought mutual support would be a benefit for all involved.
It takes time to establish a business. It takes time to raise children to ages where they can be relied on to take care of their chores without supervision and following up on them. Havin a large family means going back to baby stages every couple of years.
Everyone has the same number of hours in a day. The gain is that it doesn't take twice as long to make twice as much food, and an extra "grown up" on the team is way more + than - for sure!