I'm happy to be proven wrong and of course this is only anecdotally but I was watching sci-fi movies at age 10 and I could grasp, at least on the surface, the underlying technology and it's purpose. When we say "kids dont understand money" I'm thinking they should start to get it at about 7 and certainly have a basic grasp by 10.
When I was 7 years old, I distinctly remember telling my dad "I give you all my money" (my parents never had money, and had a few pretty rough periods). At the time I did not make the rationalization that the money was coming from him anyway, but I sure knew giving it to him meant I would not be able to buy my candies and stuff.
I also didn't really understand what his job meant, but I knew it was among the "stuff that needs to get done even if you don't like it and don't know why you have to", of which I had my own share (cleaning the room, etc).
It was never a (big) problem when he or my mom weren't around for reasons we didn't understand; what mattered was that when they were with us they were WITH US. Reading, telling stories or listening to ours, going hiking or playing sports, teaching maths or showing how to beat an egg.
Kids will fully understand what is brainwashed (used in a positive way) into them.
If they are raised to believe that work is necessary and the spouse who is with them while the working spouse is away doesn't whine, complain or fight with them about it then they will learn that it is something necessary. And guess what? If they don't that's to bad. You do what you think is in the best interest of your children long term not short term because you won't be around. In no way are they going to understand why you can't be at the ball game or the school play but later if you are out of work and/or you can't pay for their college that they will understand and they won't say "oh that's ok at least you came and saw me make that basket".
I didn't grow up with a lot of money so, again anecdotally, I'm pretty sure I had a great respect for what money could afford by that age.
There's a difference between saying kids aren't capable and kid's aren't commonly knowledgeable or taught. I'll agree with the latter but I'd disagree with the former.
