Don't get me wrong..., I think the video is great, and I am both thrilled at what they have accomplished, and jealous that I never was able to even try anything like that with my kids.
But, most families wouldn't last a week on an Open 40 - especially if the kids were much older...
I think this really is a special situation. There have been other instances of families doing extended cruising - even circumnavigations - on boats that most would not think are suitable, mostly because the boats were pretty small.
It really takes the right kind of people.
I also think that you are more likely to be successful, when the kids are young..., and compliant.
I had a somewhat unusual upbringing at about the age of those kids.., and I really remember very little of it. Some days I think it was a huge benefit, but on other days, I figure I was too young for it to make any significant difference