Even if it was allowed, I expect that homeschooling wouldn't be an option for the vast majority of parents, because most parents can't afford to stay at home teaching instead of generating income needed for rent and food. Besides: not everyone is "built" to teach effectively and most people lack basic pedagogic principles and methods. I can only encourage every parent to try teaching your children something not on the school system curriculum every day for a whole year. It takes huge effort to do so consistently for even 1h/day