I'm pretty sure that's not how household income is determined.

Multiple families don't file one big tax form because they live in the same house. Each family files separate taxes. I had roommates in college and we didn't file joint tax returns because we lived in the same house.

But by reducing their housing costs and perhaps swapping out babysitting and saving money on child care, they're able to use that money to build wealth.

Which seems like a smart idea to me. I don't see what there is to criticize.

And what's wrong with nepotism?

I'm pretty sure that's not how household income is determined.

Multiple families don't file one big tax form because they live in the same house. Each family files separate taxes.

But by reducing their housing costs and perhaps swapping out babysitting and saving money on child care, they're able to use that money to build wealth.

Which seems like a smart idea to me. I don't see what there is to criticize there.

And what's wrong with nepotism?