Mate, sustainability for families is just "can you keep the batteries charged AND the kids entertained without losing your mind" — everything else is marketing nonsense.
Seriously though, the schooling bit @Brummie mentioned is the killer. You can bodge a Victron setup in your sleep, but explaining to your 8-year-old why the internet's down again because clouds exist is a different beast entirely. My mate tried it with three kids and lasted 14 months before admitting the compromise wasn't worth it.
The genuine sustainable bit isn't the solar panels — it's whether your family actually wants to live that way or if someone's been reading too much Instagram. Massive difference.