> The reason why this doesn't work is that we have to pay for the services that help all of society. Fireman, police, roads, electricity, making sure that the food we eat is basically healthy. You could argue that "you" are a special person who will never rely on society for anything. You'll make your own clothes, fight your own wars or whatever. But we are all related.

It does work. Modern society has agreed upon on taxing earned income to provide shared services. That's where the money to pay for all the things you describe comes from. The roads, firemen, police, you name it. It all comes from income taxes (or that and real estate taxes for some of the local stuff but primarily income tax).

By taking care of your grandchildren and generally being helpful to your kids, they're covering you end of all of those as well. They earn the money that buys you food. They earn the money that puts a roof on your head at night. And all that money would be taxed per usual. Arguably you'd be paying more taxes in this setup that if each of you split out and made a more meager existence due to the progressive nature of taxes (i.e. your son making $50K pays more than if each of you made $25K).