Single income households are quite rare these days. In the US and Europe about 30%. In addition to that the parent needs the qualification and resources and time to actually teach.
This practically excludes all but the affluent upper-middle-class (the exception being extremely religious people who want to keep kids out of society for ideological reasons).
This family is pretty much the perfect example. She comes from oil money and her parents had the resources and connections to send her to a university lab at age 12.
Typically a homeschooling family (about 1% of households in the US) plan their lives around it, which makes it available to lower economic tiers within middle class, and occasionally lower class. It is not something that incidentally happens as income rises. A typical homeschool co-op will have a mix of blue-collar and white-collar careers among the parents who provide income.
This practically excludes all but the affluent upper-middle-class (the exception being extremely religious people who want to keep kids out of society for ideological reasons).
This family is pretty much the perfect example. She comes from oil money and her parents had the resources and connections to send her to a university lab at age 12.