It is remarkable. I have one child, and it is by far the hardest thing I've ever done - far harder than any job I've had. It doesn't help that both parents are working full time. Maybe parenting has changed recently and we are too hands-on, but I can't imagine having 2, much less 3+ running around. Even if one of us stops working to raise the kids full time, it's way more taxing, physically and mentally, than working a white collar job and paying for child care.
I recall before we lived in nuclear families [somewhat recent phenomenon] communal raising was commonplace. Grandparents, aunts, uncles, neigbours, etc. would come help.
