School is still the best option, there's a lot to gain here..
Not considering the time to be spent in educating them. Parents have to work to fend for the family..
That is true. And in most of the cases, the parents may not be qualified enough to educate their children (don't get me wrong, teaching is a high-skilled profession and not everyone is capable of doing it). Also, teaching requires 6- 7 hours of effort everyday. I am not sure whether the parents can afford to spend that much time, outside their full-time job.